Oh, that changes things. So, Bitwarden can be used basically anywhere, as you said. Just log in and there you are. It’s even a website. They’re servers would have to die for it to be a problem. But that’s not a real problem actually as the app keeps a local copy on the device and every time you open the app, it syncs with their servers and updates the vault (database). So the devices are synced by default really. If you want to back it up anyway, there is a „export vault” button which you can use. If you choose with encryption it’s going to be encrypted with the master password I think :)
PS Bitwarden (company) stores only the encrypted version on their servers so that’s not an issue either