Watching @CraftComputing's video on the 45HomeLab HL15 server. For around $2200 for a full-build server with 32 GB of RAM that can support 15x 3.5" hard drives is a lot better than the TrueNAS Mini XL+ 8x 3.5" hard drives with 64 GB of RAM at about $3000.
If the HL15 were out when I was building up my new NAS, I probably would have gone with that over the TrueNAS X+ that I picked up. The X+ configuration has 32 GB of RAM, same as the HL15.
The HL15 has fewer CPU cores (6) vs the X+/XL+'s 8 cores, but the X+/XL+ are Intel C3000-series Atom cores versus full Xeon cores. Plus, you can stuff the HL15 with a lot more RAM, network cards and other PCIe cards. The tradeoff is size and noise, of course.