In the middle of an install of a sub amp and sub box under back seat and speakers in doors and tweeters replaced with focal speakers. All this in my 2019 AT4. From what I understand, if your door speakers have the Bose badge then you amp/tuner is behind the back seat. There is a T harness available but I tapped into the yellow/yellow black wire for sub and went into a LC2 converter (you can google the LC2). If your doors do not have a Bose badge the your amp/tuner is under the glove box. There is nothing in the dash but the display and there is zero room behind the display. I can only assume all this is still true for your year model.