I'll post my solution for anyone searching in the future.

I used Vesktop, it took a long time to load, and I had to sign in again. So far I'm connecting for voice with no problem.

Thank you everyone for your help, I appreciate your time.

Never been an avid user of the Discord app, preferring using on browsers. But from what I remember of a friend commenting on his misadventures with that, compatibility with Linux can be very spotty. Some times the integration was broken because of the display (XServer, Wayland, etc.), or because of the desktop environment (Gnome, Cinnamon, etc.), or because of where Discord came from (e.g. Flathub, snap, the official DEB installer), or the position of the planets (joke... probably).

You may want to play around with combinations given that.

Tbh, you're in for more hassles when you get it to start. I keep having trouble getting voice to work right. Enough so that I don't even waste time trying any more, I just use a different device for discord voice while playing on the deck.

There's some weird shit going on with microphones in specific, be it wired or Bluetooth headsets. I can hear fine, but not be heard. I know I'm not the only person it happens to, but it isn't everyone, so maybe you'll be fine.

As far as it loading in the first place, if you're installing from the package manager app, it should be working. It was for me last week, maybe week before; that's the last time I tried. I'm not able to crack my deck out currently, but I'll check and see when I can and try to remember to come back if I run into problems and leave a separate comment.

I'm using Vesktop and it seems to be working fine, but I also don't use it that actively or frequently. But when I do, no issues. I'm on a generic (also arch based) Linux install, not the steam deck in particular. Might be worth a shot if other options fail.

Try Fluxer