Looks like this may be a case of the driver not liking the NVMe Drive I chose. I put the original tiny ssd in, and it picked up just fine. I now have windows installed there and fully updated. I can’t get the WD Black nvme drive to get past the driver updates. I also tried swapping it back in after all the firmware updates, and still no good. As far as I can tell online the WD and Samsungs have all the same specs, and are comparable devices.
I’m going to try eventually with the recommended Samsung NVMe 960 pro, after a while. For now I’m just happy to have gotten it back online. It is definitely faster, even with the stock ssd. boots almost instantly.
I probably wouldn’t have even thought of doing this, if my HDD hadn’t crashed completely.
Thanks for all the suggestions!!