Your best bet is to use the 3-2-1 backup system and update your backup medium periodically to stay current with technology.

3 copies 2 on different medium 1 stored off-site

There are others that are variants of this but this is pretty secure other than a world apocalypse event when you’ll have bigger concerns.

This is why I love the md array in Unraid. If I was to lose 1 data drive and 2 parity drives at once (unlikely), I’d still only lose the data on the single failed data drive, not the entire array as the data isn’t striped across all drives.

Yes it’s a bit slower but it’s my media server so still plenty fast for that.