If I recall correctly the maximum Noise Reduction Rating (NRR) for earplugs and earmuffs is around 30db. You can combine the two for a slight increase in hearing protection but you still hit a limit because of bone vibration.
Is there PPE out there to go even further beyond this? Where would it be commonly used?
Holy shit, buddy. Yes. We flip a signal 180 degrees out of phase and that added pressure pushes the outside wave down. There is at no point a reduction of pressure in your ear, it’s just more pressure that makes it so you can’t hear the sound you are trying to remove. The perception of sound and air pressure are not the same thing.
Bro. It’s not “just more pressure.” It’s literally less pressure.
If there are water waves moving a boat up and down, and you actively apply some movement (ha! pressure!) to the water so you generate waves that cancel the existing ones so that the boat stands still, would you say “but you don’t understand, the boat is getting MORE PRESSURE!!! It’s being damaged!!!”? Of course not. It’s pretty much the same principle.
Get a highschool physics book, read the chapter about sound, and come back. Otherwise, just stop.