My room is almost identical in size.
It has 2x 7.1 setups wired from one reciever.
No regrets.
Maybe one, I want better speakers.
Axioms stay.
_________________________
3 M80HP
2 QS8
2 QS4
RX-A1010
ADA 1000-4
PT-AE8000
PS4
Seymour XD
7'x 12'x 21' cave
3 Paradigm subs