A 12 gauge shotgun's primary drawback is recoil. It's the "artillery" of home defense, yes. The original post was about a home defense weapon for a newbie -- and it might be a female.
The kind of long gun that a 5' 10" adult man can handle is more than most 5' 3" women can handle.
I want to recommend a gun that fits anybody. For a woman who is new to firearms, it should be something she'll actually practice with. Not fire 10 times in one range trip shortly after she buys it, only to put the gun in her closet and NEVER fire it again, because she hates shooting that beast.
Also, a shotgun's minimum barrel length of 18" means it's going to be longer than a carbine which can have as low as a 16" barrel while staying out of NFA classification.
All the suggestions about registered SBRs and suppressors are nonresponsive to the original post. Those are for serious gun lovers with a big budget. New gun owners who just want a basic self-protection tool are not going to spend $2000 and complete pages and pages of paperwork and wait months for ATF approval.
Anything that's covered by the NFA is not a good option.
I've got about $500 in my 12" pistol build. $600 with the primary Arms red dot and flash light.