well you don't need to buy a new mobo just cause your ssd slot is bad, they make adapters to put it into an open pci slot assuming that its not a disabled because of other ports you are using like what happens on my asus tuf, very annoying.
you wont be able to boot from it i dont think?, just put your nvme that you boot from in the working motherboard slot and put your other drive in something like that so you can use it in a pcie slot
Amazon.com: Bejavr M.2 NVME to PCIe 3.0/4.0 x4 Adapter, NVME/AHCI SSD to PCIe Expansion Card with Aluminum Heatsink Solution, Supports PCI-Express X4 X8 X16 Slots : Electronics
edit: so i just noticed your motherboard pic is different then the manual pic, you dont have a pcie port on your board that could use this after putting in your video card, i think they do make usb 3 nvme adapters but is it worth it at that point? i don't know how fast they are. if you dont want to buy a new mobo you can transfer your data onto the bigger drive and use that in your one working slot, other then that i am out of suggestions. or rma your mobo if you can.