Somewhere in the bios will be a pcie option, it will look like “4x4x8” or “8x8” or some combination of the like. Most dell workstations and servers have this option that I have run into. If you don’t see this in the bios then you will only be able to run one nvme ssd
Get as slow as you can, pcie 4 nvmes get pretty toasty and without proper cooling they will throttle anyway. Either that or make sure you get cooling options.
Not all adapter cards are the same or will run every ssd in every motherboard. I have half a dozen of those things because one brand will work in one computer with one type of ssd and not in any others.
If you get one with multiple, make sure your motherboard can split your pcie lanes so you can access all ssds on the card. Or find one with a pcie switch, though that can slow things down if you are not careful.
Stay away from dell and hp branded stuff unless it is going into a dell or hp. Dell made this awesome four ssd card with fan and everything, can only get it to run in dells.
The Linux Command Line is a book I still go back and look stuff up in.