It is rather convenient that way, that's how I ended up with Mint, tried a few distro's and in the end one was left which I now use.

Also, my testmachines are less powerful than my main machines so if it performs well on the old testrig it will run even better on the main machine.
I love KDE. It's the only reason why I didn't stay on Mint. Cinnamon is good, MATE is okay, XFCE is usable, but KDE is where it's at for me, and Mint stopped having a KDE version years ago. Some folks say you can just install KDE over top of it, but it doesn't take long for issues to start cropping up as Mint has tailored repositories and little add-ons that muck around with KDE.
It's why I don't add desktop environments to certain distros unless those distros are made to be compatible with those desktop environments. I mean, yes, I *could* do it, but I have to take responsibility if and when some major conflict arises and messes up the entire system, and I'd rather not deal with that.
There are very few cutting edge distros that interface well with KDE. Fedora is one that does.
Kubuntu is another one that is more up to date and uses KDE (and has the massive Debian/Ubuntu repository), I strongly dislike Snap, and the more Canonical pushes Snap on people, the less likely I am to ever go back.
Now, of course, Fedora's talking about adding telemetry starting in Fedora 40. That's got me concerned, because while I like the people at Fedora, the steering committee, the user base, I'm not a fan of IBM, who owns Red Hat, who is upstream of Fedora, and who has people on the Fedora committee. So even if I trust Fedora, I don't trust IBM, and Red Hat's not seen as favorable because of their recent changes on their formerly open source code being made closed source.
Data is forever on the internet. Who I trust today I will need to trust tomorrow.