Do you use it on the stock ROM or on GrapheneOS/ another system?
GrapheneOS for example applies some “app optimisations” after system updates, and because of that, Kvaesitso gets some performance issues, namely extreme stuttering.
When reinstall the app or delete some data, it works again. Did you try that?
Proton is just the compatibility layer, which allows you to play Windows games on Linux.
It’s one of the main reasons so many people switched to Linux in the last months and years, since Proton gets even better from week to week. Something, games designed for Windows run even better on Linux (Proton) than on Windows!
From what I’ve heard, requiring Proton isn’t that bad, especially for the devs. Often, games engineered for Windows run better on Linux than the same ones for Linux.