Feddit.de runs well on a hetzner 2core, 4gig ram vps. (Single-core felt a bit sloppy, so go for 2+ cores.)
As for the distro, doesn’t really make much of a difference, as lemmy is run in docker containers

You can just take the smallest vps available and it will be sufficient, unless your instance is very large. For distributions Ubuntu or Debian should be easiest.