[solved - kinda] Discord push-to-talk and wayland

Has anyone tried to solve this problem yet?

Anyway, if anyone is interested, the solution is this:
KDE system settings → legacy X11 app support → As above, plus any key typed…

Unfortunately it works only for keyboard, for mouse I guess I’ll have to put a script on the mouse button for some keyboard shortcut like alt + ctrl + whatever or something like that.