Oh, this is interesting (and a little scary)
tl;dr don’t use SSDs for long term, offline storage. The data degrades after as little as two years without the drives being powered up
https://www.tomshardware.com/pc-components/storage/unpowered-ssd-endurance-investigation-finds-severe-data-loss-and-performance-issues-reminds-us-of-the-importance-of-refreshing-backups