One of ASRock’s DeskMeet miniature desktops seem to support 2 x 3.5" disks, NVMe AND ECC memory if using a CPU that supports such. See this thread for some further information;
These are limited in expandability, but that goes with all small form factor PCs.
Note I don’t know about the other models, (supporting 2 x 3.5" or ECC memory), as I was only looking for modern socket AMD, (aka AM5).