True, it is just that 3950x came out quite a few months later after Zen 2 architecture was announced as a flagship CPU. So, the question is... how long of a wait?[...] it might be worth waiting a couple of weeks to see what Zen 3 turns out like, since memory latency is meant to be one of its big improvements over Zen 2.
I just built a similar spec portable server that might be just what you are looking for. PM me if you want some tips on what to look out for when building that type of server. There were quite a few tricks that you need to do with that mb to keep it cool and quiet. I also have several of the pcie 4.0 dual port 100GE mellanox NICs that work in the 1 available pcie 4.0 x16 slot.3950x + X570D4I-2T (Newegg) + 4 x M474A4G43MB1-CTD (Neobits) + PCIe 4.0 NVMe = an awesome IPMI enabled app box which will be hella fast and won't break the bank.