I had this exact same problem on my 2004 Denali about 6 years ago.
I tried epoxy and clamps for 24 hours. Looked great and was strong. Put it in and broke 2 days later. Longer story but didn't hold.
I bought the new housing with door on ebay, then installed. No problem since.
I can say it is difficult getting into some areas for the clips that hold 2 halves together. I took pics and have instructions saved I can post later this week, if you still need it.
Doable. Take your time. I think the second time I took 4 hours or so.