diff --git a/cardano-testnet/src/Testnet/Defaults.hs b/cardano-testnet/src/Testnet/Defaults.hs
index 32029b6333c..2c1a062301e 100644
--- a/cardano-testnet/src/Testnet/Defaults.hs
+++ b/cardano-testnet/src/Testnet/Defaults.hs
@@ -58,8 +58,9 @@ import           Prelude
 import           Control.Monad.Identity (Identity)
 import           Data.Aeson (ToJSON (..), Value, (.=))
 import qualified Data.Aeson as Aeson
-import qualified Data.Aeson.Key as Key
-import qualified Data.Aeson.KeyMap as KeyMapAeson
+import qualified Data.Aeson.Key as Aeson
+import qualified Data.Aeson.KeyMap as Aeson
+import           Data.Bifunctor (bimap)
 import qualified Data.Default.Class as DefaultClass
 import           Data.Proxy
 import           Data.Ratio
@@ -152,195 +153,115 @@ defaultConwayGenesis =
 
 -- | Configuration value that allows you to hardfork to any Cardano era
 -- at epoch 0.
-defaultYamlHardforkViaConfig :: ShelleyBasedEra era -> KeyMapAeson.KeyMap Aeson.Value
+defaultYamlHardforkViaConfig :: ShelleyBasedEra era -> Aeson.KeyMap Aeson.Value
 defaultYamlHardforkViaConfig sbe =
-  mconcat $ concat
-    [ defaultYamlConfig
-    , tracers
-    , protocolVersions sbe
-    , hardforkViaConfig sbe
-    ]
-
+  defaultYamlConfig
+    <> tracers
+    <> protocolVersions sbe
+    <> hardforkViaConfig sbe
  where
   -- The protocol version number gets used by block producing nodes as part
   -- of the system for agreeing on and synchronising protocol updates.
   -- NB: We follow the mainnet protocol versions and assume the latest
   -- protocol version for a given era that has had an intraera hardfork.
-  protocolVersions :: ShelleyBasedEra era -> [KeyMapAeson.KeyMap Aeson.Value]
+  protocolVersions :: ShelleyBasedEra era -> Aeson.KeyMap Aeson.Value
   protocolVersions sbe' =
-    case sbe' of
-      ShelleyBasedEraShelley ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("LastKnownBlockVersion-Major", Aeson.Number 2)
-          , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
-          , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
-          ]
-      ShelleyBasedEraAllegra ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("LastKnownBlockVersion-Major", Aeson.Number 3)
-          , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
-          , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
-          ]
-      ShelleyBasedEraMary ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("LastKnownBlockVersion-Major", Aeson.Number 4)
-          , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
-          , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
-          ]
-      ShelleyBasedEraAlonzo ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("LastKnownBlockVersion-Major", Aeson.Number 5)
-          , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
-          , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
-          ]
-      ShelleyBasedEraBabbage ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("LastKnownBlockVersion-Major", Aeson.Number 8)
-          , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
-          , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
-          ]
-      ShelleyBasedEraConway ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("LastKnownBlockVersion-Major", Aeson.Number 9)
-          , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
-          , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
-          ]
+    Aeson.fromList
+      [case sbe' of
+        ShelleyBasedEraShelley -> ("LastKnownBlockVersion-Major", Aeson.Number 2)
+        ShelleyBasedEraAllegra -> ("LastKnownBlockVersion-Major", Aeson.Number 3)
+        ShelleyBasedEraMary -> ("LastKnownBlockVersion-Major", Aeson.Number 4)
+        ShelleyBasedEraAlonzo -> ("LastKnownBlockVersion-Major", Aeson.Number 5)
+        ShelleyBasedEraBabbage -> ("LastKnownBlockVersion-Major", Aeson.Number 8)
+        ShelleyBasedEraConway -> ("LastKnownBlockVersion-Major", Aeson.Number 9)
+      , ("LastKnownBlockVersion-Minor", Aeson.Number 0)
+      , ("LastKnownBlockVersion-Alt", Aeson.Number 0)
+      ]
 
   -- Allows a direct hardfork to an era of your choice via the configuration.
   -- This removes the usual requirement for submitting an update proposal,
   -- waiting for the protocol to change and then restarting the nodes.
-  hardforkViaConfig :: ShelleyBasedEra era -> [KeyMapAeson.KeyMap Aeson.Value]
+  hardforkViaConfig :: ShelleyBasedEra era -> Aeson.KeyMap Aeson.Value
   hardforkViaConfig sbe' =
-    case sbe' of
-      ShelleyBasedEraShelley ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-          , ("ExperimentalProtocolsEnabled", Aeson.Bool True)
-          , ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
-          ]
-      ShelleyBasedEraAllegra ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-          , ("ExperimentalProtocolsEnabled", Aeson.Bool True)
-          , ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
-          ]
-      ShelleyBasedEraMary ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-          , ("ExperimentalProtocolsEnabled", Aeson.Bool True)
-          , ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
-          , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
-          ]
-      ShelleyBasedEraAlonzo ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-          , ("ExperimentalProtocolsEnabled", Aeson.Bool True)
-          , ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
-          , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAlonzoHardForkAtEpoch", Aeson.Number 0)
-          ]
-      ShelleyBasedEraBabbage ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-          , ("ExperimentalProtocolsEnabled", Aeson.Bool True)
-          , ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
-          , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAlonzoHardForkAtEpoch", Aeson.Number 0)
-          , ("TestBabbageHardForkAtEpoch", Aeson.Number 0)
-          ]
-      ShelleyBasedEraConway ->
-        map (uncurry KeyMapAeson.singleton)
-          [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-          , ("ExperimentalProtocolsEnabled", Aeson.Bool True)
-          , ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
-          , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
-          , ("TestAlonzoHardForkAtEpoch", Aeson.Number 0)
-          , ("TestBabbageHardForkAtEpoch", Aeson.Number 0)
-          , ("TestConwayHardForkAtEpoch", Aeson.Number 0)
-          ]
-
-
-  -- | Various tracers we can turn on or off
-  tracers :: [KeyMapAeson.KeyMap Aeson.Value]
-  tracers = map (\(k,v) -> KeyMapAeson.singleton (Key.fromText k) v)
-    [ (proxyName (Proxy @TraceBlockFetchClient), Aeson.Bool False)
-    , (proxyName (Proxy @TraceBlockFetchDecisions), Aeson.Bool False)
-    , (proxyName (Proxy @TraceBlockFetchProtocol), Aeson.Bool False)
-    , (proxyName (Proxy @TraceBlockFetchProtocolSerialised), Aeson.Bool False)
-    , (proxyName (Proxy @TraceBlockFetchServer), Aeson.Bool False)
-    , (proxyName (Proxy @TraceBlockchainTime), Aeson.Bool True)
-    , (proxyName (Proxy @TraceChainDB), Aeson.Bool True)
-    , (proxyName (Proxy @TraceChainSyncClient), Aeson.Bool False)
-    , (proxyName (Proxy @TraceChainSyncBlockServer), Aeson.Bool False)
-    , (proxyName (Proxy @TraceChainSyncHeaderServer), Aeson.Bool False)
-    , (proxyName (Proxy @TraceChainSyncProtocol), Aeson.Bool False)
-    , (proxyName (Proxy @TraceDnsResolver), Aeson.Bool True)
-    , (proxyName (Proxy @TraceDnsSubscription), Aeson.Bool True)
-    , (proxyName (Proxy @TraceErrorPolicy), Aeson.Bool True)
-    , (proxyName (Proxy @TraceLocalErrorPolicy), Aeson.Bool True)
-    , (proxyName (Proxy @TraceForge), Aeson.Bool True)
-    , (proxyName (Proxy @TraceHandshake), Aeson.Bool False)
-    , (proxyName (Proxy @TraceIpSubscription), Aeson.Bool True)
-    , (proxyName (Proxy @TraceLocalRootPeers), Aeson.Bool True)
-    , (proxyName (Proxy @TracePublicRootPeers), Aeson.Bool True)
-    , (proxyName (Proxy @TracePeerSelection), Aeson.Bool True)
-    , (proxyName (Proxy @TracePeerSelection), Aeson.Bool False)
-    , (proxyName (Proxy @TracePeerSelectionActions), Aeson.Bool True)
-    , (proxyName (Proxy @TraceConnectionManager), Aeson.Bool True)
-    , (proxyName (Proxy @TraceServer), Aeson.Bool True)
-    , (proxyName (Proxy @TraceLocalConnectionManager), Aeson.Bool False)
-    , (proxyName (Proxy @TraceLocalServer), Aeson.Bool False)
-    , (proxyName (Proxy @TraceLocalChainSyncProtocol), Aeson.Bool False)
-    , (proxyName (Proxy @TraceLocalHandshake), Aeson.Bool False)
-    , (proxyName (Proxy @TraceLocalTxSubmissionProtocol), Aeson.Bool False)
-    , (proxyName (Proxy @TraceLocalTxSubmissionServer), Aeson.Bool False)
-    , (proxyName (Proxy @TraceMempool), Aeson.Bool True)
-    , (proxyName (Proxy @TraceMux), Aeson.Bool False)
-    , (proxyName (Proxy @TraceTxInbound), Aeson.Bool False)
-    , (proxyName (Proxy @TraceTxOutbound), Aeson.Bool False)
-    , (proxyName (Proxy @TraceTxSubmissionProtocol), Aeson.Bool False)
-    ]
-
-defaultScribes :: Aeson.Value
-defaultScribes =
-  Aeson.Array $ Vector.fromList
-    [ Aeson.Array $ Vector.fromList ["FileSK","logs/mainnet.log"]
-    , Aeson.Array $ Vector.fromList ["StdoutSK","stdout"]
+    Aeson.fromList $
+      [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
+      , ("ExperimentalProtocolsEnabled", Aeson.Bool True) ]
+      ++ (case sbe' of
+            ShelleyBasedEraShelley ->
+                [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0) ]
+            ShelleyBasedEraAllegra ->
+                [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
+                ]
+            ShelleyBasedEraMary ->
+                [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
+                , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
+                ]
+            ShelleyBasedEraAlonzo ->
+                [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
+                , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAlonzoHardForkAtEpoch", Aeson.Number 0)
+                ]
+            ShelleyBasedEraBabbage ->
+                [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
+                , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAlonzoHardForkAtEpoch", Aeson.Number 0)
+                , ("TestBabbageHardForkAtEpoch", Aeson.Number 0)
+                ]
+            ShelleyBasedEraConway ->
+                [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAllegraHardForkAtEpoch", Aeson.Number 0)
+                , ("TestMaryHardForkAtEpoch", Aeson.Number 0)
+                , ("TestAlonzoHardForkAtEpoch", Aeson.Number 0)
+                , ("TestBabbageHardForkAtEpoch", Aeson.Number 0)
+                , ("TestConwayHardForkAtEpoch", Aeson.Number 0)
+                ])
+    -- | Various tracers we can turn on or off
+  tracers :: Aeson.KeyMap Aeson.Value
+  tracers = Aeson.fromList $ map (bimap Aeson.fromText Aeson.Bool)
+    [ (proxyName (Proxy @TraceBlockFetchClient), False)
+    , (proxyName (Proxy @TraceBlockFetchDecisions), False)
+    , (proxyName (Proxy @TraceBlockFetchProtocol), False)
+    , (proxyName (Proxy @TraceBlockFetchProtocolSerialised), False)
+    , (proxyName (Proxy @TraceBlockFetchServer), False)
+    , (proxyName (Proxy @TraceBlockchainTime), True)
+    , (proxyName (Proxy @TraceChainDB), True)
+    , (proxyName (Proxy @TraceChainSyncClient), False)
+    , (proxyName (Proxy @TraceChainSyncBlockServer), False)
+    , (proxyName (Proxy @TraceChainSyncHeaderServer), False)
+    , (proxyName (Proxy @TraceChainSyncProtocol), False)
+    , (proxyName (Proxy @TraceDnsResolver), True)
+    , (proxyName (Proxy @TraceDnsSubscription), True)
+    , (proxyName (Proxy @TraceErrorPolicy), True)
+    , (proxyName (Proxy @TraceLocalErrorPolicy), True)
+    , (proxyName (Proxy @TraceForge), True)
+    , (proxyName (Proxy @TraceHandshake), False)
+    , (proxyName (Proxy @TraceIpSubscription), True)
+    , (proxyName (Proxy @TraceLocalRootPeers), True)
+    , (proxyName (Proxy @TracePublicRootPeers), True)
+    , (proxyName (Proxy @TracePeerSelection), True)
+    , (proxyName (Proxy @TracePeerSelectionActions), True)
+    , (proxyName (Proxy @TraceConnectionManager), True)
+    , (proxyName (Proxy @TraceServer), True)
+    , (proxyName (Proxy @TraceLocalConnectionManager), False)
+    , (proxyName (Proxy @TraceLocalServer), False)
+    , (proxyName (Proxy @TraceLocalChainSyncProtocol), False)
+    , (proxyName (Proxy @TraceLocalHandshake), False)
+    , (proxyName (Proxy @TraceLocalTxSubmissionProtocol), False)
+    , (proxyName (Proxy @TraceLocalTxSubmissionServer), False)
+    , (proxyName (Proxy @TraceMempool), True)
+    , (proxyName (Proxy @TraceMux), False)
+    , (proxyName (Proxy @TraceTxInbound), False)
+    , (proxyName (Proxy @TraceTxOutbound), False)
+    , (proxyName (Proxy @TraceTxSubmissionProtocol), False)
     ]
-
-
-rotationObject :: Aeson.Value
-rotationObject =
-  Aeson.Object $
-    mconcat $ map (uncurry KeyMapAeson.singleton)
-      [ ("rpLogLimitBytes", Aeson.Number 5000000)
-      , ("rpKeepFilesNum", Aeson.Number 3)
-      , ("rpMaxAgeHours", Aeson.Number 24)
-      ]
-
-setupScribes :: Aeson.Value
-setupScribes =
-  Aeson.Array $ Vector.fromList
-    [ Aeson.Object $ mconcat $ map (uncurry KeyMapAeson.singleton)
-        [ ("scKind", "FileSK")
-        , ("scName", "logs/node.log")
-        , ("scFormat", "ScJson")
-        ]
-    , Aeson.Object $ mconcat $ map (uncurry KeyMapAeson.singleton)
-        [ ("scKind", "StdoutSK")
-        , ("scName", "stdout")
-        , ("scFormat", "ScJson")
-        ]
-    ]
-
-defaultYamlConfig :: [KeyMapAeson.KeyMap Aeson.Value]
+    
+defaultYamlConfig :: Aeson.KeyMap Aeson.Value
 defaultYamlConfig =
-  map (uncurry KeyMapAeson.singleton)
+  Aeson.fromList
     [
     -- The consensus protocol to use
       ("Protocol", "Cardano")
@@ -386,6 +307,34 @@ defaultYamlConfig =
     ]
   where
     genesisPath era = Aeson.String $ Text.pack $ defaultGenesisFilepath era
+    defaultScribes :: Aeson.Value
+    defaultScribes =
+      Aeson.Array $ Vector.fromList
+        [ Aeson.Array $ Vector.fromList ["FileSK","logs/mainnet.log"]
+        , Aeson.Array $ Vector.fromList ["StdoutSK","stdout"]
+        ]
+    rotationObject :: Aeson.Value
+    rotationObject =
+      Aeson.Object $
+        mconcat $ map (uncurry Aeson.singleton)
+          [ ("rpLogLimitBytes", Aeson.Number 5000000)
+          , ("rpKeepFilesNum", Aeson.Number 3)
+          , ("rpMaxAgeHours", Aeson.Number 24)
+          ]
+    setupScribes :: Aeson.Value
+    setupScribes =
+      Aeson.Array $ Vector.fromList
+        [ Aeson.Object $ mconcat $ map (uncurry Aeson.singleton)
+            [ ("scKind", "FileSK")
+            , ("scName", "logs/node.log")
+            , ("scFormat", "ScJson")
+            ]
+        , Aeson.Object $ mconcat $ map (uncurry Aeson.singleton)
+            [ ("scKind", "StdoutSK")
+            , ("scName", "stdout")
+            , ("scFormat", "ScJson")
+            ]
+        ]
 
 -- | We need a Byron genesis in order to be able to hardfork to the later Shelley based eras.
 -- The values here don't matter as the testnet conditions are ultimately determined