Some pull requests on the Godot Github propose that the issue is audio setups with multiple channels, ie surround sounds ones such as 5.1 or 7.1. In your instructions, you also mention changing the format to 1 or 2 channels as well as changing to 44100 Hz. Would you be able to confirm whether your mic works when using 44100 Hz but more than 2 channels? (assuming that's something your settings allow)
testing at 44100hz 24bit 4 channels yields no detection from the game from a brief test. lowering it back down to 44100 24bit 2 channels DOES yield detection. additionally, trying 96000hz (my usual) on 24bit 4 channels AND 96000 24bit 2 channels yields no detection either. hopefully that answers the question but if not id be happy to elaborate