I'll echo Pauly and add- the suck out problem, as I know it, typically arises when people put their speakers to either side of the FP, which may look grand but as all of you are aware, has to be dealt with. Hard to predict in the abstract how it would affect sound on a side wall and apart from the hole (FP), you might wonder what the rock sounds like (as opposed to sheetrock or whatever lines your interior walls).
Agree, set up and optimize- I did a move several years ago, and even with the same system, it took me time to dial it in.
I don't like aftermarket acoustic treatment generally, but use unobtrusive bass traps and window treatment, not uncommon...
Even if somebody digitally mapped your room it's not the last word, it will be ears in my estimation. If you need help, talk to several somebodies who have done rooms. You can learn from their mistakes. I'd pause before I spend a fortune on room treatment. Some of this may be in positioning of equipment and sweet spot.
This is just the beginning....
and good luck!