You have to use proton experimental to get it to boot, but I've been getting a pretty solid 30fps with decent visuals

It sounds like it runs pretty well on the deck! I'm excited to try it too once I'm done with bg3

Baldur's Gate 1 and 2 have both held up well in my opinion. I still play through them every couple of years and have a blast every time. The enhanced editions are worth playing over the originals for the various improvements they've added.

If you do start with BG1 I'd read a little bit for tips on how to get started. Since you start as a level 1 character the game can be pretty brutal. You'll die in just a couple hits and it can be frustrating. The enhanced editions have difficulty levels, though, including a story mode where you can't be killed.

Once you know what you're doing and have gained a level or two the game opens up and is fantastic. Also if you beat BG1 you can import your character into BG2 with any permanent stat bonuses you found along the way.

The BG2 story is better and the voice acting is great. It's truly a masterpiece imo.

If you're really struggling to click with a game, I've found watching a "let's play" on YouTube helps me out.