Extreme echo/reverb removal distorted audio

I'm afraid you stand no realistic chance with this at all. The problem is that you are trying to remove something that's identical to the signal you want - which makes differentiation impossible. Even if you feed the signal into a delay, invert the result and add it (which amounts to a subtraction) it's not going to work, because a fraction of a second after you've fed this signal to the delay, you'd be sending the one you want to remove to it as well - so the whole thing will either cancel out, or, more likely, get turned into a cacophony.