There are native Apple drivers now for the Mellanox ConnectX cards (only 4,5,6) via com.apple.DriverKit-AppleEthernetMLX5.dext
I have a 25gbe Mellanox ConnectX-5 nic off ebay in a Sonnet Echo Express SEL Thunderbolt to PCIe box running on MacOS 14.7 - I paid around $300 total for the card and enclosure on ebay.
