Design a gamepad's controls in TouchOSC on a phone, send them over Wi-Fi as OSC to an ESP32-S3, and let the ESP32-S3 present them to a computer as a USB gamepad: the computer sees a gamepad, and the player plays a layout of their own.

The Bluetooth sibling of the Wi-Fi recipe: design a gamepad's controls in TouchOSC on a phone, send them as MIDI over Bluetooth LE to a board built on Nordic's nRF52840, and let the board present them to a computer as a USB gamepad, with no Wi-Fi network in between.

Swap the Gametrak's own circuit board for your own microcontroller, wired or wireless.