i honestly can't fathom how they can't fathom what OP is describing, it's the literal definition of bifurcation.
aliexpress has countless options for x8x8, x8x4x4, and x4x4x4x4 risers, all for absurdly cheap prices.
being able to use these on older platforms will really enable getting the most out of ITX builds like my mum has (modded Awyun A1-1001, 3rd gen intel i3).