SSDs at the end of their lifespan do tend to fail more gracefully than HDDs, as even when they become fully worn and unable to take new writes, they will often still allow reads.
But, that depends on the specific type of failure.
I had an SSD fail in the same way as yours, where the controller chip or something along the path there died, and it went from fully working to toast in an instant.
Some drives are more reliable, some drives are less reliable, but the only rule is that any drive can break, at any time, old or new.
Always have backups.
Sounds like you’ve got quite the esoteric setup, hehe :)
My personal solution isn’t exactly small as I have two identical four-disk NAS servers which operate with one as primary and the other as a read-only mirror of the primary. For off-site I don’t have an automated solution but just backup onto external every so often and leave it with a family member.
A good solution could be as simple as a raspberry pi with an external SSD at a friend or family’s place, and then make that accessible via VPN to your home network.