This board in your picture in what I circle the main chip (is STM32?) - is called EJoy (short for EasyJoy32), an USB controller for joysticks, ready to use.
You install this EJoy in joysticks(throttle and etc) in place of MMjoy2, not an "aggregator" board for MMjoy2. Apples and Oranges.
Based on specifications in ED forum EJoy (EasyJoy32) don't support CD4021B - so is not an easy option for Thrustmaster FCLS, F22PRO...
