Jeez, what a poor use of data center SSD’s. I’d install them in a server and use them. Note that Intel has various grades even of “enterprise” SSD’s, with the ones intended for low write load using QLC and likely not having such great data retention either.

For backups, ideally you want a tape drive. Failing that, if the data volume is not too large, optical media like DVD-R or maybe BD-R. Otherwise, I don’t have a good suggestion other than online storage that is kept spinning and maintained. Don’t use spun-down hard drives without considerable redundancy. They are horribly unreliable.

My own stuff (encrypted using Borg Backup) is in Hetzner Storage Box which is around 11 euro/month for 5TB. Every so often I get an email saying that the box will be unavailable on such-and-such date/time due to maintenance. I assume that means a drive in the RAID array has failed and they are replacing and rebuilding it.