@Migueldeicaza little late to reply, but years ago I went with a DS1618+ w/additional M2 card for SSD file caching. Was great/solid, you likely won’t regret. It’s still going at a friend’s house, but I found it limiting due to the drive matching requirements, so I moved on to Unraid on a dedicated PC that took its place. Arc is great backup software for Macs, could also use Time Machine. Unraid has been superb over the years since, neither system lost data for us.