With Ubuntu and RHEL clones out, what's in these days? Debian?
If you want enterprise support, Leap is binary compatible with SUSE Linux Enterprise.
I work at SUSE so I’m obviously biased here but I really do think the OpenSUSE ecosystem hits the right balance for a very large majority of users and use-cases.
Personally, after more than a decade on Ubuntu, I finally moved to Fedora last year. While I don't have any major complaints, Tumbleweed does look tempting.
You probably can use Mint on a server but for me, the obvious Debian-like server distro is Debian itself. I can't imagine one advantage of running Mint on a server. Mint is focused on the desktop.
On the desktop, Mint really seems like Ubuntu without snaps, and a specific package management that is way more conservative when it comes to upgrades. And a focus on Cinnamon and Mate.
On the desktop I would formerly advise Ubuntu. Today, I would just suggest Debian, which is the distro I trust the most, or maybe Mint. I just don't see any scenario where Ubuntu could be better than either of them.
I use openSUSE Tumbleweed myself. I would not recommend it to a novice user. openSUSE Leap might be a solid choice but I never tried it so it's difficult to recommend it.