Question about ASUS ROG Theta 7.1

I bought this product a few months ago and it is impossible to set it to 7.1. Either the "Armoury Crate" software doesn't detect it, or it doesn't offer any 7.1 mode. I also noticed that every time someone talks into the headset (or into a game), a very annoying little noise is heard. I'm on Windows 11... I hope this is not the problem.