HX8369 TFT driver was grabbed from the demo source code came with the board with slight modifications, as it was originally written for LVGL. Some wrappers were added to make it work with embedded-graphics crate. It may work on other boards with HX8369 display with correct parameters set in hx8369.h, but it's not tested.
The GT911 driver is not fully functional, it doesn't support multi-touch and the way it's being used may be completely wrong.