There are still Badboys for sale here at Island Waterworld. I can’t test the thing at the moment as the boat is away for the hurricane season.
I did do the same tests as you for connectivity and found the connection quality much better at lower levels and away from the mast. Most marinas I’ve been either have a domestic router working so bad (congestion) it makes no sense to use them anyway or they use several directional antennas pointed at the different pontoons. The latter assumes connection at lower levels.
From experience I prefer using a 3/4G SIM & router to save myself the annoyance of Acces point congestion you get in most “free” WiFi spots.