2933 is slow for b-die. A "typical" premium kit is 3200 C14-14-14.
OEMs like gskill take stock "2133/2400/2666" b-die chips from samsung, "bin" them (supposedly) and can run some of them all the way up to 4666 now. Pretty sure I saw a bare shot of one of the 4000+ kits was just plain old 2133 bgas. Samsung actually sells stock 3200 dies at 1.2V ("in mass production") but I've not seen any actual kits with them - its not even a JEDEC speed yet.
The only reason you don't see faster ECC is the intersection of "factory overclocked ram" and "servers" has been zero before threadripper happened. (which is really anything not JEDEC and not officially supported in the cpu spec sheet: ryzen 2xxx are the first cpus to list 2933 official) Xeons always hard lock the memory speeds.
I don't count the few dozen of us on the planet that bothered to source unlocked xeons and put them on desktop boards, intel killed that completely after haswell anyways (may they be infested with the fleas from a thousand camels for that).
Zen ecc ram shopping, buy smart, buy b-die:
M391A1K43BB1: 8GB sr
M391A2K43BB1: 16GB dr
F24EA8GS: 8GB sr
F24EB16GS, F24VEB16GS: 16GB dr
For non-ecc shopping you want 3200 14-14-14, 3600 15-15-15, 3600 16-16-16 or better. Pay special attention to all 3 cas timings, otherwise it might be hynix or micron, not worth the trouble on amd. Gskill and Team are the only brands I see that regularly sell these kits, don't bother with Corsair.
Personally I go for ecc, it takes a little more effort to dial in timings but same price range, sometimes cheaper! Ram is nuts now.