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.
The native build of this game crashes a lot and the proton one has awful performance issue, especially after around 100 turns. Even on the lowest setting. Not sure why it’s advertised as having native Linux support. The new content doesn’t make it more playable.