I think the situation is generally better on AMD platforms than Intel ones, but still YMMV.
https://forum.level1techs.com/t/any-lga1700-motherboards-wit...
Some boards will only bifurcate the x16 slots into x8/x8 mode, which is sufficient for an x8 GPU with one SSD attached to the spare lanes, but that still leaves 4 lanes unutilized. Adding two SSDs to fill up the bus requires support for x8/x4/x4 mode, and an x16 carrier for four SSDs requires support for x4/x4/x4/x4 mode.