Have you tried switching to X11 for these games? I have had similar problems on wayland. wayland is still beta-ish imo.
I always did make -j$(nproc --ignore=1)
to avoid this while building cpp code. But this problem seems to be less severe if there are a lot of cores.
I think this was the setting https://www.maketecheasier.com/a-look-at-kde-desktop-effects/
Few years back I had to fiddle with the kwin rendering backend and select egl for nvidia.
It a website with silmiar news to other sites with almost no ads, no paywall, no open in mobile app, plus rss works. I barely post a few times a week. Not sure if thats a lot.
It’s not that bad imo, probably good UX wise. People using gnome have a specific mindset/expectation that usually does not apply to people using KDE (and reverse).
Most of the heavy lifting is done by lower level libs anyway. So the duplication is not as extreme. E.g Firefox doesn’t gel well with KDE by default. And thunderbird looks quite foreign.