Samsung 970 EVO Plus NVMe is a solid performance drive for your system.  The choice of 1TB or 2TB will depend on your usage needs.  A lower per GB price for 2TB is a wasted value if you don't need such large storage.Your PCIe adapter link does not work, although the MHQJRH adapter with heatsink solution is a performer for its low cost, it's not the best brands in comparison to StarTech or Ableconn. When an M.2 solid state drive with notation M keyed or B keyed, it's referred to the cut-off section at the drive connector end which allowed only the correct type of drive to be installed to the M.2 slot.  In your case, the PCIe adapter will accept M keyed, a fitment designation for NVMe (or AHCI) solid state drive.  While a B keyed or B/M keyed is designated for M.2 SATA solid state drive.  If interested, you can learn how to distinguish the differences between M.2 cards.I can confirm that your selection of the solid state drive and the PCIe adapter should work well with your Dell XPS 8930.  You can even make it as a boot drive should you choose.I hope that I have provided all the clarifications to the information you have sought and they should give you enough confidence in your decision making.
I have the PCI Express x4 card slot. It only looks to be a little under 2 inches long. I am wanting to buya Samsung 970 evo NVme. Not sure about if I am going to get 2tb or 1tb. Only 30 dollars difference inprice. The adapter I want to use is from MHQJRH. Not sure if that is a good brand or not. I am going totry and link it here. It says it is only to be used with M key and not B key. Not sure what that means. BeforeI order it, I want to make sure it will work with my Dell. I have windows 10. I already have a small NVme thatcame from Dell for my C drive and two HDD drives. Now let me see if I can link it 0652260?pd_rd_w=0t4K0&content-id=amzn1.sym.116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_p=116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_r=CD29P6162EDA3ED1CDX8&pd_rd_wg=nHgVI&pd_rd_r=b1099568-9736-4441-9481-351a4b9c42df&pd_rd_i=B07JJTVGZM&psc=1
XPS 8930 Question about installing a NVme 2.0