I also have a 2023 AT4X purchased new in May of this year. The AC has never worked properly! The dealer cannot fix the problem and says it is likely a firmware/software problem. With the AC system set on "Auto", at vehicle start-up, the blower works properly for about3 to 5 seconds, and then the blower speed steps down as if I were making a phone call. The blower will stay at this lower speed until I actually make or receive a phone call or until I do a work-around of the problem by pressing the manual fan UP speed twice and then putting AC system back into "Auto" mode. The system then works as it should. This is especially troublesome when outside temps in west Texas are 105° and temps in the cab are likely 115° plus. This can be a distraction while driving as well and could create liability for GM were there to be an accident due to this distraction.
For a vehicle that cost upwards of $90K, you would think that GM could allocate someone to develop a software fix. A large GM dealer in the Dallas, TX area told me that other owners are having this problem as well. This tells me that it is not due to some erroneous setting made during initial vehicle set-up.
Come on GM, you can do better than this!