Third time’s the charm! It wasn’t easy- I actually completely crashed my system and had to do a complete reinstall of Windows, but once I went into Bios and slowed the PCIe slot speed to Gen3, the last adapter worked. So I’m finally up and running after two weeks of troubleshooting. I now have three 4tb NVMe SSDs mounted, plus a 2TB external drive with USB for 14TB total. I’m happy to share more details if anyone else is dealing with something similar.