I think it comes down to preference. I definitely don't think KDE is amateur, but it certainly lacks the fine polish Apple has the money to pay for.

That said, I find MacOS frustrating at times because basic things can feel like a pain. Switching between several windows of the same application isn't a simple Alt-Tab; the green button enters full screen mode (KDE/Windows F11 Full Screen is equivalent) instead of leaving just the menu bars and application bar on screen; tiling windows isn't as simple as ramming the application against the border you want to expand to. These are simple things I do often in other OS's that have tedious menu workflows in MacOS. I still like a lot of MacOS though.