My room is the exact same size as yours.I went with carpet and a good quality underlay to cut down on reflections and not have it too lively.
I have 78 inch high, 16 inch round ASC tube traps in all 4 corners with absorbtion at the 1st and 2nd reflection points.
I have 78 inch high, 16 inch round ASC tube traps in all 4 corners with absorbtion at the 1st and 2nd reflection points.