This is great info, thank you. If you were going to go forward with the change, did you decide on Truenas or Unraid? I'm pretty sure truenas wont work for my use-case anyway.
Question for you:
1. do you think its worth factory resetting the readynas OS install? I was considering imaging this so I could retain a copy just in case. I'm still really annoyed by how Netgear handled the EOL process on this.
2. Did you notice anything strange compatibility-wise with the Readynas box RAID controller setup and Unraid? My goal currently is to re-purpose my 10TB drives in the readynas and add in the 2x 20TB drives I just got (which currently backup my 20TB google drive takeout).
The setup on Unraid would be: 20TB parity, 20TB drive, 4x10TB drives.