Gaming

Baba Is You, Into The Breach, Ultima VII (with Exult)

Deus Ex is a great one (and you can even play the Randomizer mod in Linux)

Stronghold Crusaders, or Command and Conquer.

Nostalgic childhood games.

caves of qud is quite good, its tile based roguelike.

Backpack hero is very cute and fun, and runs very well through proton.

One Hour One Life and Two Hours One Life (open source) can be run on pretty much any computer.
The concept is: you're born as a baby or a fertile woman and you have to gather and build to survive. Your maximum age is 60 years (OHOL) or 120 years (2HOL) and you hunt, gather, build tools, have babies and raise them. You can become the matriarch of a huge multigenerational family and build towns, buildings, farms, roads and weapons. People keep adding to it, I haven't played in awhile but I think they have cars and airplanes now.
The graphics are MS Paint-quality but the gameplay is so incredibly fun. Highly recommend.

If you install ScummVM you can play most of the Lucasarts titles! All of these games are top tier (Monkey Island, day of the Tentacle etc) and you would enjoy!

I recommend Baldurs Gate, BD 2. Good games. Also Planescape Torment.

Starsector. Sseth has a really good review of the game.

Gta san andreas, works perfectly fine with the newest wine-ge and dxvk 2.2 but you can try without dxvk if your computer doesnt support vulkan renderer

ofc battery drains if not connected to the electricity network man, these graphics card are not meant to run games if not when they are charging

Anyway you can try SuperTux and Xonotic

Cave Story is good / hectic / hard platformer. I might be wrong but I think it was made for Linux first

Also, if you install RetroArch, you can play all the emulated systems.