Wait I though it was Windows that had a KDEy feel? Anyway it shouldn't matter whether UI's have some common features if they're good, only whether we like one regardless. You enjoy GNOME, great, that's a very slick desktop too.
Plasma has a lot of things that puts it above Windows in my book.
Yeah, I also had apps like Steam native break once or twice due to library updates (such as Mesa) - the downside to rolling distros. However, the Flatpak version continued to work so now I only use that. I don't use mods though.
I'm now gravitating towards treating my rolling distro a bit like an immutable; more Flatpaks, avoid user repositories.