

Main reason is that if you don’t already have the right key, VPN doesn’t even respond, it’s just a black hole where all packets get dropped. SSH on the other hand will respond whether or not you have a password or a key, which lets the attacker know that there’s something there listening.
That’s not to say SSH is insecure, I think it’s fine to expose once you take some basic steps to lock it down, just answering the question.
Lots of ways to get around that without having to go the route of burning a hundred blu-rays with complicated (and risky) archive splitting and merging. Just a handful of external HDDs that you “zfs send” to and cycle on some regular schedule would handle that. So buy 3 drives, backup your data to all 3 of them, then unplug 2 and put them somewhere safe (desk at work, friend or family member’s house, etc.). Continue backing up to the one you keep local for the next ~month and then rotate the drives. So at any given time you have a on-site copy that’s up-to-date, and two off-site copies that are no more than 1 and 2 months old respectively. Immune to ransomware, accidental deletion, fire, flood, etc. and super easy to maintain and restore from.