Proton on Kubuntu

So I started making some small games using SDL2 and C/C++, and they work on my Steam Deck, but when I try to run them in Kubuntu they have strange bugs. They were compiled on my Windows 11 computer. The best results I've gotten so far are with Proton 9.0-4. As I have been making reusable components to build all my games, they share a lot of code.

Some small games I made so far: Flappy Bird, Breakout, Frogger.
Frogger works as expected.
Breakout works but is way too fast.
Flappy Bird: the game runs, but the pipes stop at the far left and never reset to the right.

Strangely, all these games run perfectly on Windows 11 and the Steam Deck. I was expecting the same results on Kubuntu. Any advice would be great. I do plan to make Linux builds as well, but I was surprised that a game that works on SteamOS doesn't work on Kubuntu.
(These games are not going to be published, as they are just tests, and I can't publish rip-offs of other games)

reddit.com
u/Patrick-W-McMahon — 4 days ago

Just recently started out.

Mostly doing game streaming. Will be adding more IRL streams of life later on, after I finish my studies. I will also add some programming streams.

twitch.tv
u/Patrick-W-McMahon — 12 days ago