Greetings @bgo,
I can’t comment too much in detail regarding this display/touchscreen since I’m unfamiliar with it. Assuming everything is hooked up correctly from a hardware point of view, I can only look at your overlay.
Looking specifically at the part of the overlay where you specify the touchscreen details. How did you create this part of the overlay? When I check the in-kernel documentation for this: ilitek,ili2xxx.txt « input « bindings « devicetree « Documentation - linux-toradex.git - Linux kernel for Apalis, Colibri and Verdin modules
The example device tree node is a lot simpler than what you have. You also have a some undocumented fields like ilitek,vbus, ilitek,reset-gpio, and more.
Best Regards,
Jeremias