What type of backup do you use?

As needed, which is usually after significant updates, I

1. export both 1PUX and CSV from the desktop app,
2. import the 1PUX data into two other password managers,
3. encrypt the 1PUX and CSV files,
4. save the encrypted files in a local archive, and
5. save the encrypted files in encrypted "cloud" storage.

This more than satisfies the 3-2-1 Backup Rule and provides an working alternative password manager for everything except passkeys in the event that I cannot use 1Password, while safely storing all my data on systems which I control in a form which I can use.

The files themselves are so small that all can be kept, effectively giving me an accessible archive of all data I've ever added.

Be sure to periodically test recovering data from those SD cards. While you are in no danger of wearing out the storage with writes, the fragile components are sensitive to the physical environment.