Debian

It's not server-oriented. There are people who have used it as a desktop for 25 years.

Debian is the upstream for almost everything now. IMO, the more layers are added to Debian, the more delays or errors that can be introduced. For example, Mint was famously withholding security updates a few years ago. Ubuntu has snaps which have been consistently problematic ... enough that I switched to Debian on three systems because routine updates would routinely break Firefox.

Flatpaks have closed the gap. It is entirely possible to have up to date user applications on a stable, secure base system. Now that the Debian installer includes non-free firmware by default, the downstream distros are really just adding pretty wallpapers and color schemes. Not really worth it for the added overhead.

So I just cut out the middle man and go straight to the source.

Just my opinion, I've learned to appreciate Debian after 25 years of avoiding it and using every other distro you can think of.

I started out on Ubuntu back when it was basically just Debian with more stuff preconfigured and newer packages.
So I'm intimately familiar with the .deb ecosystem.
Moved away from Ubuntu when they started trying to push their own solutions over accepted standards (Unity, Upstart, Snap) and included ads in their OS.
Moving downstream to a Ubuntu-based distro felt wrong so I moved upstream to Debian instead.

I don't think it's the best distro out there in all respects, but it's rock solid, dependable, predictable and I know it inside out.
Plus, it lets you choose how up-to-date vs. stable you want it to be, with its testing and unstable branches, backports, apt-pinning and third-party support. And also, how bare-bones you want it to be, since it offers a minimal installation with less hassle than Arch as well as a full bells-and-whistles system with its default installation.

Imo, why ask the question with the assumption "is based on a server-oriented distro" when "dektop distros" such as Ubuntu, Linux mint Zorin are then using debian? It is a bit conflicting isn't it? it all boils down to personal taste, if you like ubuntu, use ubuntu, if you like linux mint, go use that. If you want to use debian or arch or fedora, you know...

For me it is easy enough, stable enough, bleeding edge enough (testing/sid) to tinker around without invading my machine with stuff I don't necessary want