I've been following this thread for a few months, so decided to join to share my experience...
2019 Silverado (slider window), purchased at the end of March.
Realized it was leaking in November when headliner was soaked and there was water on the inside of the door and on the rear seat (not sure how I didn't notice it before). Brought it in to the dealership, they had their "water leak expert" guy look at it and "seal" it, which was putting some sealant along the window. Rained again a week or so later, still leaking - not as bad, but still has water coming in. Took it back to the dealership, had the same guy come out and basically do the same thing. Week later, still leaking, same amount as before. I immediately call, didn't hear back. It was around the holidays, so I waited for it to rain again, and then called again. They left me a VM saying they'll contact their "water leak expert" again and have me come back. I called and left a message saying I'd like to take a different approach to this since attempt 1 and 2 clearly didn't work. They never called me back. I left at least two more messages with the person I was dealing with.
I decided to open a case with Chevy as several as you suggested. My customer rep reached out to the dealership and said I'd have to bring it back in for an "updated diagnostic" even though it's already been in there twice. She also mentioned that the service manager said that a new window wouldn't necessarily be covered by a warranty. So I guess it's fine that a brand new truck is leaking water. We left it at I was going to call and make an appointment, but considering calling my rep back and saying I'd prefer to go to a different dealership at this point especially since there are closer ones to my house.
