Same Issue with my 2019 1500 Silverado Crew Cab. Weather doesn't seem to make a difference but I notice it most at very low speeds. Mine started about 22K. Tried putting antiseize on the back of the brake pads and caliper pins. I also cleaned off a good amount of brake dust built up by the brake hardware. This did seem to stop the squeal for a few days but then it came back as bad as ever.
I think I share the same sentiments as every one else here that it is very annoying for a brand new truck. I have never had another vehicle that would do this so regularly. The only other time I have had a vehicle squeak when I stopped was when the rotors were wet...but that was very rare and went away after a couple of stops. This happens almost at least once EVERY time I drive my truck!
When I had the calipers apart, my brake pads appear to barely be worn. I think my service department is such a joke that I would rather just try new brake pads myself. I usually buy OEM parts, but I might look around for a better brake pad from an aftermarket supplier in this instance.