Using wireless headphones on Linux is very easy and convenient.
1) Turn the headphones on.
2) Open terminal and run alsamixer, because ALSA by default drops left channel volume to 0.
3) Choose a right sound card in alsamixer and raise the volume to 100.
4) Now keep in mind that in some cases it means that Pipewire will borrow volume levels from ALSA. You don't want to hear 100 volume in your headphones.
5) Change the system volume in Pipewire. It still will be shown as your default level (say, I use 30 in my headphones), but it's actually 100 borrowed from ALSA. So any change will just "remind" Pipewire to follow its own settings, not ALSA's. Don't forget it doesn't happen every time, just sometimes.
6) And you're golden! Don't forget to do it again after reboot.
7) Oh, I forgot. Keep in mind that you better choose right sound profile in PulseAudio for your headphones and make sure it doesn't conflict with your Pipewire sound profile if your DE lets you tinker with it. Thankfully, usually you only have to do it once.
Nice and easy.