SolidRun has a MiniITX board supporting up to 2x32GB for around $1000 [0]. They also have a preproduction units for another board for $550 supporting as much RAM [1].

They probably had their reasons, but I'm just showing what's available.

https://www.solid-run.com/product/SRLX216S00D00GE064C13CH/

https://www.solid-run.com/nxp-lx2160a-family/honeycomb-works...