Synology Upgrade Swap!

Hi all! I have a quick question on upgrading my Synology Setup.

  1. I have a DS1522+ filled with 5 18TB Drives with 1 drive tolerance. I also have a Ds220+ with a 18TB and 16TB drive, RAID 0 which backups the main Synology via hyper backup. All of this works perfectly, but I do not have an offsite backup.

  2. I want to purchase the Dx517 Unit and take 2 drives from the Main to add to the DX unit. This way the DS 220+ becomes the offsite backup instead of being the onsite backup of the main.

I just saw Spacerex’s video on this, but my fear is finding the best way to reduce the 1522+ so that it’s only using 3 of the 5 hard drives without losing data (All of the data is currently on the Ds220+ via Hyperbackup)

What is the best way of approaching this? 🫶🏼