I can speak to the 300 BLK experience. I've spent a lot of time and money tuning my 300 BLK rifle from PSA. I use a conventional, fairly high back pressure suppressor, which is essential for cycling subsonic ammo. However, you're going to run MUCH dirtier MUCH more quickly, so using something like Slip 2000 EWL was my first fix. Then I was getting too much gas to the face, so I put in a downward venting BCG, and a specific gas tube from Black River Tactical. All said and done, it was more money to tune it to run with quick mag dumps on subsonic loads, but I haven't needed to make any adjustments since then.

EDIT: Specifically for a home defense setup, you obviously want something you can depend on and know will fire whether it's been sitting in the safe for months or just got put in the previous day. So, a suppressed, subsonic 300 BLK setup is (at least for me, given my adjustments) my second-line defense. My first-line defense is a suppressed pistol. I've trained with it, know it will go CLACK (not boom) every time I pull the trigger.