I've been down this rabbit hole and it's not a good option for standard matx or mini itx. Best I did was get a supermicro board and a supermicro 1u half-depth chassis. It was OK for a while, but the HDDs did not cool off very well.
I've now not got a nas just as fast with a radxa rock 2a, a penta sata hat, some FPC cables between them and some cable bodging in a jonsbo n1 case. Drives are happy, less power consumed.