After a hiatus in Mac and windows land, I came back into Linux a with similar wishlist.
It's quite a diversion, but I actually went with FreeBSD. Now it's not Linux but with the separation of base system and packages, you get a stable base that is released at a pretty fixed consistent schedule.
For packages you can pick from quarterly or weekly update schedule, so you can have a stable base OS with bleeding edge software. The binary package manager is easy to use, but if you want more control you can opt for building from source as well.
The init system is BSD based so all main config goes into a single rc.conf file, very easy to understand and work with.
Most mainstream applications such as Firefox, postgresql, nginx etc are just a pkg install away and it natively supports zfs (even as root fs) which was one of the reasons I got really interested in it 10 years ago.
Of course, there is software, especially some younger projects that don't support FreeBSD. So while there are thousands of packages available, some Linux only applications won't work.
Personally, I would pick FreeBSD any time that the software I require supports it. I only run Linux (settled on pop is for now) if the software I need requires it.
I don't know if I should upvote you for having it on your list or downvote you for not having watched it already...