Bought a 2021 TB on April 11, 2022. It had just arrived at the dealership and I bought it sight unseen over the phone. The dealership would NOT, NOT allow me to take delivery until ALL lifters in both banks were replaced first per GM. This was the first I had heard of a lifter issue. I'm at 15k miles and no issues.
I did have an issue with the seatbelt buckle rubbing my center console and scratching the crap out of it. Turns out a piece of felt that goes on the back to prevent this issue was forgotten. I contacted GM corporate and received an immediate relpy. They wanted pictures and wanted me to take it to the dealership ASAP. They corrected the felt issue and replaced my entire center console under warranty. After completed, I received follow ups from GM corporate. I couldn't be happier with how GM took care of me, independent of the dealership.
If anyone is having an issue with their truck, consider a nice professional business letter to CEO Marry Bara like I sent off. While she did not directly reply, someone made absolutely sure I was taken care of.