It seems like the issue could be related to a few things, such as the wiring for the trailer, the trailer brake controller, or even the adapter. Since your 2023 3500 High Country recognizes the trailer brakes but not the lights, I would suggest double-checking the adapter compatibility with the truck and ensuring the wiring is correctly connected. Also, it could be worth inspecting the trailer's LED lights to ensure they are functioning correctly with the vehicle’s electrical system. It may also be useful to try a different adapter or test the truck’s trailer wiring with another trailer
