I pretty much instantly wrote off physical media because I know I won't reliably move it to a separate location. If I'm going to have backups, I want ones that are not within fire/flood range of my computer.
In terms of preventing "oops" moments, I'm mainly relying on software (restic) for that, where I trust that (A) backups always append data rather than replacing and (B) it's logic works for marking which data to purge based on rules is accurate. [0]
[0] https://restic.readthedocs.io/en/stable/060_forget.html#remo...
You want to make sure the append only is enforced by the hosting provider rather than duplicity. Your backups should be resistant to having an attacker on the system who can run arbitrary commands with duplicity.