I live in Alaska and I’m an out avid outdoorsman, I hunt fish trap and shoot ultra long range here. I have 1000 pound bears that live on the creek behind my house that is full of salmon… When I’m caring one of my rifles I have my side pistol which is a Smith & Wesson .500 with .700 grain bullets hand loaded. If you have to shoot it it’s like a hand grenade going off in your hand! When I don’t have my rifle, I carry a Keltech KSG shotgun.
That's definitely not a plinker!
I have fired an S & W 500 with the 500 grain bullet in lieu of the 350 or the 700 you cite. The 500 with a 500 is crazy heavy action out of a handgun.
If I wanted a second shot on target, I would use the Taurus Raging Bull (longer barrel than what is shown) in .454 Casull which as an old guy I can still handle. Your preference for the long gun is noted.
What types of slugs do you carry in your shotgun?