The accel/gyro is not a problem. The problem with your project is primarily the radio and secondarily the Arduino board, which has a bunch of power hungry peripherals that you don't need or want. The Nano 33 BLE sense would be a better choice.
That is fine for a crude prototyping, but for a workable watch, most people would use a low power processor, BLE for the radio (if you must have one) and a custom PCB.