BikeControl
Do virtual gear shifting (and more) in any rider app
...This allows you to perform actions like virtual gear shifting, steering, changing workout intensity, controlling music, etc., even if the trainer app doesn’t natively support those controllers. It works on different platforms: on Android, it uses the AccessibilityService API to send simulated touches to whatever app window is active; on desktop (Windows/macOS), it can emulate key/mouse input via configurable keymaps so users can tailor controls.