I absolutely adore Mocha Pro for doing screen-tracking, but it’s still no match for a device that has a ton of random reflections and glare on the screen. Sometimes using old-school tracking markers is more effective than attempting to planar-track a surface without tracking markers.
But motion tracking techniques are always full of compromises, and the biggest compromise that comes with tracking markers is that you have to remove the tracking markers in post if you want to matchmove a non-opaque element onto the surface.
In this video, I walk through a rough camera test I did for a project that required realistic screen replacement on a non-stationary Apple Watch, and the strategy I took for making the tracking marker removal less painful.