>>grabeh+(OP)
I can tell you that GDPR is going to cause issues with block based backups. Many hosting providers don't separate customers on different block devices. When you back up a block device you have snapshots that have many different organizations data on them.
Part of making good backups is knowing that the backup can't change. The only solution now is to add paths to go back and modify those backups to remove customer data when asked too.
That is my plight anyways.