I can vouch for this. Many KDE users who (generally) see the issues
you’ve raised as trivial compared to the functionality that KDE brings.
But every one has their own levels of what they will put up with. I dont
recognise your issue 2 and I suspect the X11/Wayland choice might
resolve it.
There’s a FAQ on keyboard switching which you might find worth
reading. It’s not a KDE issue.
I never presume to speak for the Qubes team.
When I comment in the Forum I speak for myself.