It's mostly libinput. Why the hell can't I easily change scroll speed on Gnome and not on KDE? Why does gnome have a simple tool (gnome tweaks) to change the trackpad cooldown to change the time trackpad doesn't work as a substitute for good palm rejection and KDE doesn't? Why is it a bit of a pain in both to change trackpad gestures? Why am I hearing again about God damn redesigning the settings placement on most desktop environments.
Edit: I love both KDE and Gnome, and I think that they're great. But it kinda hurts to see them fail on what seem like relatively simple things
You might check out xfce. It's gtk like Gnome but the development team doesn't have their heads up their asses; pretty much every aspect of xfce can be customized. It should be a simple install from your package manager, whatever distribution you're using. The downside of this, however, is it might take extensive tweaking to get it to look how you want as it's a pretty bare bones UI by default. Personally I like it, but ymmv.
That's the beautiful thing about the Linux world. If you don't like some aspect there's virtually always an alternative.