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...