Redundancy != Backup

RAID is redundancy.  Clusters are redundancy.  It's about keeping services available, not preventing data loss.

Backups are about preventing data loss.

For a long time, the 3-2-1 backup rule has been considered the most reasonable solution most of us will get.  Of course, now I see people saying it sucks.  Well, you do what you can afford, I guess.

It's worth noting that you can self host an off site backup, if you have a second physical location you can use.  It can be a relatives house or you can even rent a space on an existing server farm.  The main point is that it's not in the same building as the original copy.