I switched from Windows 10 to Nobara KDE plasma ~1 month ago. It's a Fedora based distro, so most of the Fedora documentation applies. I came from server Linux but Windows desktop (20 years or so) and I'm amazed how similar it is and reacts. It comes with Libre Office, Steam etc. pre-installed and while the Libre software is certainly different and needs getting used to - for me, coming originally from Wordperfect and Quattro Pro it was no challenge. There are some minor bugs which I attribute mostly to the Nvidia 580 graphics driver, like distorted fonts in certain mouse positions, but these are really minimal and I won't deep dive (yet) into that. Support online via discord which isn't optimal, but at least there is support.
It would help to know what it is you are not loving with Mint+Cinnamon... My picks for a beginner-friendly batteries-included Linux dist for KDE:
- You can install KDE on Mint without switching distro or reinstalling[0]
- Debian (caveat: packages can be out of date if you need the latest-greatest of something)
- Fedora (caveat: two major OS upgrades per year can feel like a chore)
- EndeavourOS (caveat: Requires a bit more expertise and grease to properly maintain)
- Aurora (caveat: Still young project and I'd still consider it a bit experimental and adventerous)
- kubuntu (caveat: snaps. Accept them or learn how to disable)
KDE Linux is a thing and something to keep an eye on but it's still in alpha/beta and probably not ready for your use just yet.
[0]: Caveat: it's possible that some DE service might not be disabled properly from your old setup and conflict with KDEs variety if you keep the cinnamon packages around
The better question would be what is the best distro for you. Personally I like Debian. But I don't know enough about you and how you use your computer to say for sure what is best for you.
I used Kubuntu for years, but ultimately moved away from the Ubuntu based distros due to Canonical cruft. I haven't really missed anything going with vanilla Debian.
I've found Gentoo Linux to be a good developer- and sysadmin-oriented distro. It requires a lot more work up-front than most any other distro but -IME- once you have it running, it just keeps running and upgrading just fine. If you wish, you can even subject yourself to systemd, as that's a supported init system.
As a bonus, if you don't want to build everything from source, there are prebuilt packages available. Instructions for how to use them are in the "Installing the base system" section of the Gentoo Handbook. I've not used the Gentoo-provided prebuilt packages, but I do use my own prebuilts. I've found the process of using them to be well-documented and fairly straightforward.
OpenSUSE has traditionally done a bunch of work on making sure other software works well with KDE (for example patching Firefox to use the KDE file chooser). Much of that work is no longer needed with new tech like the XDG desktop portal stuff, but Tumbleweed is still a fairly solid system (up to date, stable, GUI system administration tools, automatically installs packages with AVX3 if your CPU supports it,...).
Don't worry too much about distributions, they'll mostly just affect package formats and default settings, but imo Debian is the best choice for stable desktop computing, with the best overall support and community.
