Seems like alot of SuperCabs suffer from door rattles. If it makes you feel better my 2013 SuperCab rattled and my 2019 SuperCab is beginning to rattle as well. I use electrical tape on it and the rattle is 98% gone. Its a small price to pay to have the better version Raptor, SuperCab over a SuperCrew. Haha.
Yeah definitely a lot SCAB noise I've just learned to live with. I also use the tape trick though. I wish Ford would ditch the clam shell and use a B pillar with a smaller rear door. Normally I don't like the little door on the Chevy, RAM or Tundra but with a short bed it would be acceptable.