Site doesn't answer how storage is 'solved'. Is this solution uses local folder provisioning when using PostgreSQL for example.
Honestly I’m kindof surprised that something like rook it not used instead, but I guess it is easier to trust hetzner storage and hope for the best.
We host in various bare metal providers, including Hetzner. (I am the lead engineer building Ubicloud PostgreSQL, so if you have questions I can answer them)