It’s up to you. Things to consider:
- Size of data
- Recovery speed (Internet speed)
- Recovery time objective
- Recovery point objective (If you’re backing up once per day, is it okay to lose 23 hours of data when a disk fails?)
If your recovery objectives can be met with the anticipated data size and recovery speed, then you could do RAID 0 instead of RAID 1 to get higher speeds and capacity. Just know that if you do that, you better be on top of your backups because they will be needed eventually.
I’d contact Ninja support about it, but the likely answer is that it’s not possible