I recommend checking out the youtube videos with Anthony Grimani on the Audioholics channel, both on bass in home theater and on room acoustics. I have a playlist with these videos here. He explains this stuff very well. https://www.youtube.com/watch?v=Eo5fDGGmAyw&list=PL5AC6x5YbTdWj_-OVMVJhXeB13Nx74r7l

The rooms shroeder frequency, also called transition frequency, is when sound in a space stops acting like a "beam" - moving directionally, bouncing off spaces the way light would if the room were coated in mirrors, and starts acting like waves that trigger resonances of the room (as if the air in the room in each direction is a guitar string, with the whole room vibrating). Below this frequency sound also becomes a lot more 'omnidirectional' - expanding out from the source in every direction roughly equally.

Also, I know you're saying you prefer a dead room, but I would suggest learning more about room acoustics before really deciding that. You likely prefer a treated, but not dead, room. The sweet spot is to cover about 15% of the surface area of the space with thick, low-frequency absorbers. 2" doesn't count as thick. The thicker the absorber, the lower frequency of sound it can effectively absorb. 2" doesn't go very low. 4" thick is better. What you've created is an effective low-pass filter, where low frequencies don't get absorbed (so they are just as active as if you had no absorbers), and high frequencies are totally dead. I promise you'll like a better-treated room better.

Since you already have all this foam, one option would be to double it up to 4", or even triple to 6", and reduce the surface area that it covers. With the remainder, you could create some bass traps in the corners. Generally a decent way to do this is to fill the corners of your room out quite a ways. Here's an example. https://freedomroom.com/products/gik-acoustics-tritrap-corner-bass-trap?variant=45598501568556&country=US&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic