Did you get it serviced under warranty... My 21 is now making the same noise. Identical to sound yours was making!My 2021 Yukon SLT has developed a squeak when it starts.
Anyone ever heard of anything like this? Engine mounts maybe?
There is also a similar squeak when releasing the brake after slowing down quickly or when the body leans in a sharp curve at city speeds 50 km/hr (30 mph) or less.