

For what it’s worth, Synology Hybrid RAID is just a fancy GUI over linux mdraid, so the drives can be mounted on any Linux system (Synology even have instructions for how to do this on their website). You’ll be SOL mounting them with any kind of third-party NAS GUI that expects their own partition layout though.
I picked up a used 2018 Fujitsu office PC with an i5-7500 for $60 (from a physical recycle shop, with a 14 day warranty) and it draws 15W idle. Way better value than a Pi (once you’ve added case, cooling, PSU etc) for running home server stuff.
A Pi still kills for “Arduino plus plus” use cases where you need the size, GPIO or can optimize the heck out of power usage on a battery.