Yeah it’s tough ! I often end up making the decision on what I need the most . I know with Gogo you can do it on multiple but at separate times . southwest has their own providers they work with (global eagle/Panasonic ku) so I’m not sure they have that function. You should look into wireless flight routers on amazon though
Southwest should offer FREE WIFI so it wouldn’t matter about MAC addresses or authentication or any of that BS. While working for the City of Albuquerque as a network engineer, we setup FREE WIFI for the entire airport terminal 17 years ago! C’mon Southwest.
On American I discovered that their WiFi works on all of my devices, but not simultaneously. As an AList preferred passenger I have used my phone or IPad simultaneously on my SW fights often. Did you know that you can access Southwest.com without paying any fees. It makes checking on for the next day and checking flights or making reservations easy.