Eh, the way you phrased that I think it’s either fedora or opensuse. The up-to-date criteria basically knocks out everything with a fixed release cycle besides fedora which is pretty bleeding edge since they update certain things like kernel between releases.
Some criteria are non-sensical though imho. Ease of use? Speed? They are all the same, sure pacman works faster than zypper but it’s not like I’m waiting for either, they work in the background while I do stuff. As for ease of use … kde is kde, terminal is terminal. I think you would have to branch into the realm of the BSDs to get real differences there.
Debian is really solid, prefer it over any of its derivatives. You being unable to install something in kinoite is just lack of research on your part, ofc you’re going to have issues with a distro if you don’t know how to perform the most basic stuff. Stay far away from nix if kinoite gave you issues, with nix 90% of your pre-existing Linux knowledge will not only be useless but actively harmful.
Reading between the lines I think opensuse tumbleweed might work for you. Stable, powerful installer, very up to date and most of your pre-existing knowledge should transfer. Fedora is nice but you mentioned the magic word production, I don’t like fast cyclers in production, major version updates are a hassle at the best of times.