It is surprisingly very durable and maintenance-free even for a script kiddie like me to maintain. My advice is (at least when it comes to Vaultwarden) don't think too much about this, just selfhost it, at least for yourself. You'll probably be able to manage it when something happen.
and not using their official clients,
your database stays functional in perpetuity.
My host has prebuilds for Vaultwarden.
Reimplementing the server side is the easy part.
But a commercial offer will need rebranding the client, and maintaining forks is much more involved. As long as Bit warden publishes the sources ...
Theft is also usually obvious.
If self-hosting, keep at a separate location than your hard drives.