Repeating Events: last day of a month

[Solar-Simon]

If I want to set a repetition to the last ‘Friday’ of the month, this is not possible. Only every 4th is possible.

However, if I create this in another calendar app and then edit it in Etar, this option is displayed. But then every 4th day is no longer selectable.

There should be both options. Because sometimes there is a 5th repetition of a weekday, sometimes not.

Etar options

Options of a different calendar APP.
'Repeat on the same day of each month
Repeat every fourth Friday
Repeat every last Friday
Repeat on the last day of the month'