@shaknais really though how do you deal with this in practice?

tape backups cannot be used now because you can't selectively remove data

restic / borg? No, those are gonna be a problem too because, again, you can't go back and delete little pieces of old backups

ZFS snapshots? nope. can't edit them.

What are their options now? Regular disk and object storage? The backups have to be writable now

This is exactly what the ransomware people want. It makes their attacks so much easier if all your backups must be writable by law. There won't be an option to just tell them to piss off and restore from your super secure backups because they legally cannot exist