Paid help with Disability aid (XBOX game control)

HI all, I need help to finalise an Arduino project, designed to help my disabled colleague use a joystick with XBOX. The project is almost complete, but not working! Components include: 1x Itsy Bitsy, 2 x Teensy LC, Arduino libraries. I am willing top pay for your help.
I have built the board with the 3 shields, programmed all 3 with Arduino code but no joy.
The Project is described here: GitHub - gdsports/xac-joystick-splitter: Xbox Adaptive Controller Joystick Splitter
Basically this board needs to interface with the Microsoft XAC Adaptive Controller, then connect to a Logitech 3D joystick. The board allows a single hand on the Logitech to control Left and Right XBox buttons.
If you can help, you will need solid skills to test and fix both the new board and the supplied Arduino code. It may just be a bad solder joint, or it may be more. Thanks for reading.