So bottom line, there is no currently available AM5 motherboard that can run with 48GB*2EA setup?
Yeah ? That was before Sandy Bridge then because Pentium i3 to i7 of that generation didn't support it. Neither did the original Core i. Core 2 was another matter entirely since the RAM controller was part of the chipset. You could get a Core 2 duo on a workstation mobo and thus get ECC support, but note the use of "workstation".https://hardforum.com/threads/ecc-check-on-intel-i3-processors.1693051/ yeah intel has pentium with ecc... just use the right chipset.
Amd has ecc but need the motherboard be compatible... (see some working but not perfectly).
Intel have in consumer grade ecc way before the amd has the bulldozer junk and piledriver trashbin.
Amd has the blame someone else, if not work, try find support in other place.