>>107105971
After looking around a bit I think the least bad option for a high-end CPUMaXX rig would be to get the AsRock Rack TURIN2D48G-2L+ motherboard that theoretically supports up to 24 memory channels coming off of 48 DIMM slots.
Though fully filling those slots would be ridiculously expensive, if you go with "cheap" 32 GiB DIMMS you would end up with "only" 1.5 TiB of RAM.
I think I'll buy one and try to get it to work with only a single CPU + 2 96 GiB DIMMS.