ALL Genoa and later EPYC require 1 DIMM per channel (EPYC 9004 and 9005 are 12 channels) for optimal performance
any more or less results in up to 30% loss in benchmarks according to my testing.
That limits you to 192 GB loadout minimum and multiple up to 1.5TB)
I’ve built on the H13SSL-N, H13SSL-NT, and MZ33-AR1
Gigabyte is better for compute, storage applications, and huge RAM loadouts
Supermicro is better for GPU acceleration (clearance issue on gigabyte boards)
all of them can be upgraded through the IPMI with an incompatible or vendor locked CPU installed.
rev 2 is labeled on the board when they post it on eBay
I haven’t seen a sub rev 2 H13 board in the wild