I think my answer wasn’t very clear, I meant that aside from streamin, when running games on the deck directly, you can also choose the resolution the games start in, which enables you to set higher resolutions in game. Some 2D games gains massive benefits from that, because they lose that pixelated look. Rogue Legacy 2 for example at 1920x1200 is way smoother than at 800p.

No, that would be horrible, you only want fps that are Hz/2 Hz/3 Hz/4 etc. So for 80Hz that would be 80, 40, 20, 15, 8

Install BG3 on your desktop, then on the steam deck, go to baldurs gate, and instead of install or play, click on the little array to the right of it. There you should see the name of your desktop pc. Choose it, and play will change to stream. That’s it. If you want to change streaming settings, go to the remote play section in your settings. Disable hardware decoding. Turn on hvec and low latency.

Downsampling is the best thing you can do for image quality. You can also choose 1440p as the resolution for games in their properties to sometimes massively improve AA, like with Persona 5