This is what I use for plastics
There other brands and types but this is specifically the best I have found for the price.
There is better but pricey.
Pull the door panel for best results. Clean both parts to be joined with alcohol and let dry.
Mix an appropriate amount of epoxy, while it is thin, butter both halves you want to join but don't assemble yet, let it set up for 15 minutes, then assemble and hold with good tape. It will set overnight. The next day gently pull off the tape and mix more epoxy and
liberally apply it along the crack on the inside (outside too if you don't mind the look) and let set over night.