I’m currently testing Fedora KDE on a VM (windows host) before eventually switching over to Linux completely.
Plasma. It’s the most customizable and you can dive in and shape it. It feels much more natural for me to jump into.
I put xfce on older hardware.
Distro wise I tend to go with Ubuntu flavors most because they seem to have better compatibility for various software and stuff I need, but I haven’t really shopped around too hard in years. Work is RHEL (and clones) and they make me sad.