Minimum Rise Time for Microcontroller (STM32F769IIT6)
The minimum rise-time depends on as much on the output resistance of the STM32 as it depends on the capacitance on the wire. 35mm is not long. Just put the traces over a ground plane and you are good. If you think there could be some issues, put 10R resistors into the path (make sure that you still get a fast enough rise-time for the frequency you have chosen), but I doubt that this will be necessary.