I entertained all the ideas listed so far by my most intellectual friends.
I finally attached some paracord, and used wire eyelets on the ends. I drilled pilot holes in the top of the door and on the underside of the drip rail at the top of the door. Then I attached the eyelets with self tapping screws.
A few trials of what length of paracord, and it stops the door from hitting whatever.
Ken and Terry
2018 Sunseeker 2430S
and might rarely get pushed by our 2017 GMC Terrain toad (4 wheels down)
Former Georgetown 330TS owner for 10 years with more mods than I can count.