A "systemd like solution" LOL. Exactly ! As long at it's work as intended, perfect thing. But when you want to change, add or remove a thing you can't because it's far too complex tu use and really understand.
Mdadm and lvm2, both are doing a only thing but they did it well. Can't make differents raid level per file, yes. But at raid level you can do anything (reshaping, and so on)
mstdn.binfalse.de is one server in the network