I’ve done this too, but to a mid 2017 21.5” iMac. The curious thing is I’ve bent the little gold tip on 1 of each pair of connectors, but WiFi still works fine, and my BT “magic” keyboard still works, and my watch will still unlock the Mac, but BT connections that require a more complex data stream (sound, mouse movements) do not. I THINK I should be able to solder new connectors to the antenna tips, but I cannot find part numbers.