After the most recent main edition of the Heroic Games Launcher, other people discovered a factor that was preventing Proton games from working on Linux/Steam Deck. This new solution deserves to fix the problem.
What is heroic? An open-source, cross-platform game launcher for managing games from GOG, Epic Games, Amazon, and can serve as a Wine admin to install standalone apps and games.
The tweaks are minimal, as it’s a quick fix, but a must-have update if you also find the games working. Changes in Patch 1 v2. 14. 1:
More on the official website.