oh!!!! discord-screenaudio works on my new setup!!!!
i guess the reason it works on my arch and didn't on my manjaro when i tried it last year is because i'm now on wayland + pipewire when i was previously on x11 + pulseaudio. i only tried it again because i wanted a way to fix discord not being able to screenshare wayland apps, i didn't think it would actually work so well...
that was basically the last "unfixable" gripe i had with linux after using it as my main computer for a whole year so i'm stoked that i can now stream games for & watch videos together with my gals