Cool path and write-up. Thank you!

Just because of the use case, and me not having used it in an AR app while wanting to, I'd like to point to doublepoint.com 's totally different but great working approach where they trained a NN to interpret a Samsung Watch's IMU data to detect taps. They also added a mouse mode.

I think Google's OS also allows client BT mode for the device, so I think it can be paired directly as a HID, IIRC.

Not affiliated, but impressed by the funding they received :)