Thanks for the info!
I'll try Rook-Ceph, Ceph has been recommended quite a lot now, but my nvme drives sadly don't have PLP. Afaict that should still work because not all nodes will face power loss at the same time.
I'd rather start with the hardware I have and upgrade as necessary, backups are always running for emergency cases and I can't afford to replace all hard drives.
I'll join Home Operations and see what infos I can find