No, home DEFENSE does not involve maneuvering in tight quarters......CQB/Room Clearing does. Are we defending our house, or sweeping it?
Cleared rooms for real in the Corps. I’ve cleared more rooms than I can begin to count as a LEO. I teach Home Defense/CQB/Room Clearing/Active Shooter. Unless I need to secure a family member or escape my residence because it’s on fire, I’m not clearing anything. I’m gonna defend and wait for the SO to arrive. If I need to clear for one of the reasons I previously mentioned, I can easily do so with a 16” carbine.
Is a 16” carbine ideal? Probably not, but neither is a handgun. An SBR, SBS, or SMG would be just the ticket, but the OP doesn’t sound like someone that wants to go down that rabbit hole.
I’ve cleared multiple residences and commercial structures using handguns, shotguns (14” and 18”), carbines, 20” rifles, and SMG’s.
I too have cleared 100s of structures looking for armed men. Not once have I ever felt at a disadvantage because I was doing it with a carbine. Nobody that clears a house/commercial structure anywhere in the world looking for a real bad guy does it with a pistol.....unless he is forced by some archaic policy. There is a reason for that. Finally the internet myth that a pistol is the ideal tool for defense in any armed engagement is just that..... a myth. A pistol is like a pocket knife.....convenient. But when it comes time to cut off heads you need a machete. And if you can only have one to lay beside your rack, don’t choose a pocket knife.