I'm an expert in building soundproof rooms if you want help. The key to real soundproofing is double walls with no connection between the studs. Air space and air tight.
Foam on the walls will do nothing for soundproofing it is only to make the sound in the room deader.
Fiberglass or so-called Sound Board, will do very little to keep anything but some high frequencies from passing through the barrier.
If you want to keep low frequencies from getting in and out you need mass, air tight walls and doors, as well as preferably separate framing for each side of the wall with no cross brace connection.
All this and anything but a very heavy door extremely well sealed and the door will just let the sound through. It's like a small hole with a water leak, the water will find the hole and get in.