If you want a gun that ticks all the boxes, get a 12 gauge shotgun

Disagree.

First, ammo starts at a minimum of 44cpr for 00 buck. Second, unless you get mag fed shotguns--which have their own problems--you're getting a maximum of about 7 rounds. Third, if you're talking about pump guns, it's pretty easy to short stroke one in a high-stress situation. Gas guns are a different matter, but they're pickier about ammo. Fourth--again, unless you have a mag fed shotgun--reloading is not nearly as quick and easy as it is with any firearm with a magazine.

If it’s locked up, you can’t knock on the charging handle or emergency kick the charging handle to clear it.

You mortar them; that usually gets it. I've had to do that a few times.

Yeah, a detail strip and clean is a bastard. But you don't really need to do those very often. A field strip and clean is sufficient most of the time.