getting input to work on a Pico VR headset

[264312431]

im trying to get this or any variant of scrcpy to work on a pico 4. theres no public documentation afaik. it comes with bt hid controllers that let you point and click at the screen much like a wiimote. i have adb but no root. so by trial and error i found it will register taps with trackball as the source:
input trackball tap 1000 1000
that works so far. any tips where to go from here?
i guess worst case i'll have to roll my own server build ...