is it possible to install navigation on a 2020 Traverse LT, and can I do it myself without voiding the warranty?

 

As long as you don't fry the electrical system. Also, I believe that you will need to flash the system to accept it.
IMO, I would rather get a stand alone GPS. Less hassles and safer.

 

I agree. I use a Garmin 5" display that mounts on the windshield. It has all kinds of good info, like speed, elevation, time to destination, traffic avoidance,ect. and best of all a forward camera with a microphone and a flashcard. That and you can mount it in any vehicle with a 12-volt power/cig plug.