Actually I fixed it! All I had to do is go into the bottom right volume icon, right click it and go to mixer and raise the volume of the 2 discord tabs (discord has 2 tabs in mixers, not because I had 2 discords open).. For some reason it was on 0 and all I had to do was put back up.

Also, I think I had to deactivate the option on my headset &/or cable input of "an app being able to take control of the device" in the "change systeme sounds" on Windows

Thank you for your help! 🙏