So my credentials are stored in a folder called vaultwarden in the root of the server.

that's not true:

./vaultwarden with the ./ prefix means that vaultwarden will be in the same folder as your docker-compose.yml.

It looks as a good position for your setup.

Trovo rischioso aggiornare la vps se intendi mantenere i servizi attivi. Io di solito ne creo una nuova.. Ad ogni modo per postgres farei un bel pg_dump e poi pg_restore

In my case should be for my family. To separate my photos from my daughter's photos