I have a similar problem, only I was able to update the synapse but the switch between stereo and THX does not work. So far I have not received clear help, I have provided Razer support data and am waiting for a response from them.

A very annoying situation is that I cannot adjust my microphone, even if I switch between sound modes, the sound sounds the same.

I absolutely agree with you, I came after a difficult day, updated the software and then it started, the THX audio channel disappeared, through which the sound was output, the synapse became useless at all due to the fact that the only thing that is adjusted there is the volume, neither bass nor normalization changes, and THX sound does not seem to work at all. The situation makes me think about changing the headphones, namely to some other company, such as HATOR or Logitech.

I noticed that the app works when I make the computer windows 10, the app is not compatible with windows 11