Recent testing revealed that Arch Linux, Pop!_OS, and even Nobara Linux, which is maintained by a single developer, all outstripped Windows for the performance crown on Windows-native games. The testing was run at the high-end of quality settings, and Valve's Proton was used to run Windows games on Linux.
While I love good news for Linux gaming, this article is IMO a litre too positive. In the last part, notebookcheck picks the games that Linux distros were best in and presents a biased picture.
But the general message is positive: When games run under Linux, the performance is probably equal or better than with Windows. (And Windows has compatibility problems too).
Yap, ProtonDB give us a good picture, mostly games still have minor issues. But, I like this kind of thing because show potential. If gamedev do they homework, the Linux experience could be better performance.
You are right, these experiments really show that Linux is suitable for gaming, just some games aren’t running on Linux.