When I looked into it last, I planned to spend about as much as a Synology, but it would have much more compute, memory and as much storage. I was likely going to run ProxMox as a primary OS, and pass the SATA controller(s) to a TruNAS Scale VM... Alternatively, just run everything in containers under TruNAS directly.

For my backup NAS, I wound up going with a TerraMaster box and loading TruNAS Scale on it.