Cpu, ram, etc only really matter if you do a lot of transcoding. Otherwise, Jellyfin does and uses very little.
If you have a system that supports hardware transcoding (like most Intel cpus QSV), then you can get by with very little again. Otherwise, you need a lot more for software transcoding.
Storage space: a couple GB is plenty.
Linux: in general? Debian, maybe? But it doesn't really matter when you can also run it in a Docker container. Just pick something that's user-friendly for you.