The backups aren't the problem - what is the problem is Apple's "solution" to a clear bug being "don't restore from backups" (for the cellular-data draining bug).

Instead of asking you to lose all your data as a workaround to a bad bug, they should actually fix that bug properly, so that it's no longer a bug.

Likely the same with the bug described in this story - if someone ends up affected by it, they're basically pooched: they can't do any more new backups, and likely if they do restore from a previous backup where data exists that triggers this, they're just going to get into that same loop of problems.

And because it's not a "high severity" (RCE) bug, it's likely never really going to get fixed as there are "workarounds for it" (read: wipe/setup the device and omit your data) or "other mitigations implemented already (previous versions of the OS be damned!)" as noted in the story.

I don’t see any indication that Apple recommends this workaround.

I was told this by Apple when I brought up the problem through their “support” for the cellular drain issue.

For the record, so was I, but by a repair/data-wipe technician.

No but it would be nice to be able to selectively restore a subset of backups.

Backups should be able to be merged with data on the phone. The use case is I want to travel overseas but I don't want various border control entities to make copies of my phone contents, so I back it up and reset the phone to factory defaults. Then I go on my trip and take pictures and receive texts and etc. When I get home I should be able to merge the pre-trip backup and the during trip stuff into a single set of contents on my phone.

Is this how backups work with your personal computers?

Yes, if I do a full restore, I expect all files and settings to be restored, including bugs present at the time the backup was made.

iOS backup apparently doesn't work like you described. E.g., when restoring a backup from iOS 14, it doesn't revert your system to iOS 14. Clearly there's a separation of restoring the executables and restoring the configs.

I do expect "the config/setup that would trigger a battery drain in <iOS X" to be restored, but Apple can always fix iOS so that the same config/setup won't break >=iOS X.

If you do a full restore implies that you don't have to do that.

And yeah as the other commenter said, that's not really how the ios one works.