I use KDE plasma without any customization and I find it perfect. What "tinkering" is required according to you ? I even found the defaults super powerful. I got a notification on my NVMe having a failure, and I wouldn't have thought of this if it didn't show it to me.
For me it's stuff like the size of toolbars. They are too small and i tried a bunch of scaling before but couldn't get it right. The size of borders is also an issue where it seems like theres a few pixels i need to grab onto to resize a window so its difficult to do. Recently i ran into an issue in Nautilus where it doesn't auto refresh the contents of a folder when files are added, and there's no refresh button in sight either - you have to know the shortcut is F5. There's just a lot of tiny issues like that that keep cropping up. Then linux people will say "oh it works for me" and that's the end kf of the discussion.
There are also plenty of apps like Unreal or Davinci that while supported on linux tend to be more buggy just because they have a smaller user base and less investment by companies.
Yes, I get you, I also sometimes run into tiny issues when I try to shape the things how I want to be. That's why I kind of abandoned this mindset, and use as many defaults as possible. If I use KDE, I'd use the default file browser etc. I'd use the default functionalities and shortcut provided... I still run into some annoying issues (like, can't properly write with the korean characters).
For apps that "should" run on Windows (game, game dev, or other stuf), I'd just boot Windows yeah. Honestly it's so much time gained in just running the stuff how it's intended to be. As a bonus, I think it forces your brain to "adapt" to the stuff you have in hand (which sadly means that yeah, you won't be a power user most likely)
Not really a KDE thing but having multiple screens with differing refresh rates is a pain on all distros I've tested. Either you add a lot of buffering to avoid screen tearing, or you get screen tearing.
I use KDE Plasma on Fedora, Wayland, and it works in the latest kernels. I remember it was an issue for me before, but now I have my laptop screen (120Hz) and desk screen (60Hz) working well.
