However since Wayland (or at last KDE's Wayland implementation) doesn't provide any functionality for changing video modes, the bug isn't triggered when running KDE with Wayland as the latter forces games to use whatever video mode the desktop uses.
Of course that means that games that do not support 1280x720 wont work at all, but that's minor details, about as important as using a lower resolution to get better framerates from the Atom iGPU the device has :-P
(ok, actually might be possible by using gamescope[1], which runs its own Wayland+XWayland compositor inside an SDL window that you can also force to use a specific resolution - again no resolution changes are supported and that uses wlroots - that can be scaled to arbitrary outputs and if the SDL you're using has a Wayland backend to avoid going through the desktop's Wayland compositor's XWayland layer then you may not get that much lag at all - though not sure if there'd be enough memory left for the game after all that :-P)
[0] https://github.com/Plagman/gamescope - it is a fork of Valve's wayland compositor which actually works under X11 inside a window and effectively creates a nested XWayland environment but also attempts to minimize latency... it doesn't eliminate it completely but outside of twitchy shooters it is ok
Valve are not the only ones doing anything for Linux gaming, but they are a pretty fucking big contributor: - Releaseing Steam for Linux, which has encouraged many games to be ported. Yes, the Steam Consoles are cancelled (or on hold), but even the promise of a new market (and the convenience of not having to have a separate distribution channel for the Linux version of your game) has changed the Linux gaming landscape from a handful of titles to more games than anyone can play (depending on your tastes ofc). - Employing/contracting people working on different parts of the Linux graphics stack (SDL,radv,dxvk,more). - Developing Proton. I mostly play native games, but Proton has been huge for many. Yes, it's based on Wine (that is a good thing, NIH syndrome is way too common is bad) but Valve have improved the parts needed to get a good gaming experience and packaged it up in a nice way that is dead simple to use for anyone. Just click a button to play your Windows games. - Lots of other small things. For example Valve's Plagman has been working on https://github.com/Plagman/gamescope which is godsent for thos of us with ultrawide monitors or other uncommon resolutions and aspect ratios that gamedevs like to pretend don't exist.
And best of all, most of those improvements have been open source and available even to those who don't want to use Steam. That's surprisingly open for what is esentially a DRM company. So saying "The open source community is more responsible for Linux gaming than Valve" doesn't even make sense when Valve are part of that opensource community.