What Should to Do With Extra PCIe Slots?

I had an Asus HYPER X16 GEN 4 CARD for 4 Nvme but it's OK for only one slot I should change to x4x4x4x4 in my bios Another idea was to

2 Slot is from the Ryzen 7 5700G then it will only support PCIe Found is or As an example only This Asus Motherboard supports

m2 slot You're referring to NVME based M2 SSDs, correct? But yes if the SSD is PCIE spec then of course the speed will be less when used on PCIE

m2 slot screw  An 2280 solid-state drive , 22 mm wide and 80 mm long Connects to, Motherboard via one of: PCIe ×4; PCIe ×4; PCIe ×4; Serial ATA