Frsky Archer R6 with orange cube

ardupilot 4.0.7, the adsb board with orange cube
At this point I’m still trying to setup the controller and can’t get anything working. From what I was able to find, it seemed that plugging the included 3 pin connector to the RC In should be all that’s necessary (the other 3 pins are for sbus passthrough and an external sensor?).

As I searched, it seemed there were various serial settings necessary (SERIALx_PROTOCOL=10, SERIALx_OPTIONS=15 or 7, RC_OPTIONS=8, RSSI_TYPE=3). But I’ve tried every combination of these on both serial 4 and 6 (I can’t find anywhere specifying what serial the RC In actually is), and also tried switching the receiver from s port to f port, and also tried disabling telemetry in the receiver altogether).

Does anybody have any ideas? At this point I don’t even care about the telemetry, I just want a working controller without having to try and return this and buy something else.