I think it’s getting time to start research to replace my aging Synology, what’s good in the marketplace right now?

I’ve a DS 1513+ which has served us well but given the age of the disks I’m thinking build a replacement and mirror it, then archive the old HDDs as a backup.

We also have a Terramaster unit that’s pure junk, but that’s used for non-critical archival data. Only Unraid saves it from the recycler.

DS1522+ or is the 16- or 18-series worth the extra? Or is there something better for the money? The old 15-series has been rock solid, are the modern units as good?