TB3 docks and TB3 NVMe drives may require 10.12 Sierra or even 10.13 High Sierra. Check the specs before buying anything. They work well with the 2011 Mini and 2011 iMac. I have High Sierra on both of those.
mdgm..... Thanks to you and anyone else who came here to help. As for the trolls, perhaps you can give your XBoxes a break, get out of your basements and get some sunshine. Ma's meatloaf is ready!! 😁