based on your card, it should be using a decent bit of the 600w or so passed through the new 16-pin connector. goes without saying, a proper PSU (doesn't have to be ATX, but at least 750W to be on the safer side) is a must.

for thunderbolt enclosures, consider going through the list - https://egpu.io/best-egpu-buyers-guide/#tb3-enclosures

zero idea about mac support so YMMV.