Room open on 2 sides, room treatment?

Hi my living room is open to my dining room and my foyer on 2 sides, but not at the ends.

The room is rectangle shaped, with one end with mostly mini-blind covered windows. On the long sides, one is solid wall, and the other is solid wall in the middle and open on both sides.

How much can i do to treat the room? Are the open sides actually better for acoustics? Should i try to close them up somehow?

Of course i will try to cover the first reflection point. But i only have 2 corners out of 4.

Thanks for your help.