Balckhole, big sur and double audio output 2021

[yourgrandmagaming]

First, I have no idea what I am doing. I joined this website because I thought I may be able to get some answers about the program BLACKHOLE.

I want to stream League of legends off my iMac desktop, through streamlabs, and onto twitch. I got blackhole to be able to capture my desktop audio. I've set it up according to streamlabs tips and blackhole. HOWEVER when I get into my stream, I am getting audio on my stream, audio through my headset AND desktop audio (which creates an echo since I use a yeti mic to speak with my chat). I'd like to get rid of the speakers, since I am on my headset, and still have stream game sound as well. I cannot figure out how. Please help me. I am ready to buy a PC, lol.