in the early days of steering Zwift did do something through the companion app, but its been discontinued, I’m guessing because it didn’t entail people spending out on extra hardware, other than some sort of turntable that could easily be knocked up to go under the front wheel
Using gyroscopes is not a good idea as they require calibration and are liable to drift even when calibrated (some of the sensor fusion combined sensors in Android work a bit better but are still a bit flaky). I think the OP referred to using a touch screen interface instead of a sensor, but given how a mobile device touch screen behaves when it gets a few drops of sweat on it, I doubt if this would work much better. The simplest approach would seem to be just binding normal keyboard keys for steering.
I have used the Wahoo Steer device tray that you put your phone in to steer in RGT, and I ended up making a plexiglass cover to stop the sweat from dropping on the screen, and causing erratic behavior.
In RGT steering can be initiated in different ways. The gyroscopic function did not work for me. However the “tap right” or “tap left” function works perfectly, even with a little bit of sweat.
It is drop dead simple. The screen shows an arrow pointing right and an arrow pointing left. Tap an arrow and you move one lane in that direction. I think it will move multiple lanes if you hold your tap but I find it more effective to make several quick taps to move multiple lanes.