I have quite a few shotguns. I do have the Mossberg Flex in 20ga. I have the Cruiser 18" barrel and have all the different stocks. love shooting the Pistol grip. Contrary to internet garbage, it is easy to shoot. Also have the tactical stock which is nice and the standard hunting stock. I also have a slug barrel. Makes for a very versatile shotgun. While I own a number of Beretta's and Benilli's one of my favorite is the Stoeger Condor Outback OV with a 20" barrel. It is my go to deer gun. Great for the thick Brush and swamps I hunt in.Uses Beretta chokes.
By the way, here is another of my Back Packs. The 22" Turkey model even comes with a drilled and tapped scope mount. As I said, these single barrel guns accept Beretta Mobile chokes. I use the short 18" barrel for Deer when I have to do a lot of trucking through the woods. 4 1/2 lbs. is insanely light. And it groups buckshot very good.
Short lane adapters in many calibers and gauge's. All for one gun.
Am I missing something? Maybe it is the way I define "Survival" vs "Self Defense" For survival I have a marlin bolt in 22 mag. With it I can take a variety of small game and under the right circumstances a deer. That will keep meat on the table. For self defense, I have a variety of options based on whether I am defending against home intruders, armed trespassers or I am traveling in potential risk areas. BTW, potential risk areas have grown substantially in the past 12 months.
I like Shotguns too but my budget limits my choices. I have Chosen the rimfire route. I picked up a Ruger Charger back in the Spring of 2020 and have been upgrading it little by little. Survival to me means collecting food as quietly as possible with as little damage to the game as possible. I have been practicing often and have become proficient enough to feel confident with the Charger to also call it my Self Defense gun should it need to be pressed into that use. I have other bigger caliber choices but it is likely that the Charger would be there when I would need it. The 22Lr has long been a first choice in my self defense choice, and I am sure it will do the task at hand.