Looking for wider soundstage

@backdoor , It is, but I have no idea what you will accept as reasonable performance. You might be perfectly happy with a system I would deem sub par. But you have spent a lot of money already so my guess is it is important to you. If it is imaging you want the first thing you have to provide your system is a symmetrical environment. Stereo is all about symmetry. If one channel differs from the other in any way the image is chipped away at depending on the severity of the infractions and in the situation I see in your picture they are legion. 

In a residential situation with the size rooms we normally have you want a flat front wall and two clean corners That extend for at least 6 feet in front of the speakers This should be on the short wall of the room. Both speakers see a corner and the listening position will be somewhere in the middle of the room away from the back wall. If you use the long wall the listening position will be up against the opposite long wall which will really create amplitude problems. With the type of speakers you have you will need sound absorption on the front wall, side walls and ceiling. The speakers need to see an exact mirror image environment. From there if you want SOTA performance it takes a little digital signal processing which scares the h-ll out of the analog crowd. Suites me. It keeps the price of digital processors down. 

I only mean to help and do not want to see you wasting money chasing a faulty situation that might be able to improve a little but still will never approach the performance it should, the performance you expect. 

sudnh I gave your suggestion a try and I did get a bit better sounstaging. I have a few other things to try but it has become clear that room treatment is probably going to be the best thing I can do. Or find a whole new room as mijostyn suggested. Thank you. 

If the tarps help look into something durable and easily foldable like this.

I've been using tarps like these for years (mainly to cover windows during heat spells).

DeKay

You will require perfect symmetry in your listening room.  If that cannot be obtained, the first reflected surfaces will require insulation. 

You probably know this, since you referred to treatments, but the soundstage often depends on keeping out confusing reflections between speakers and ears. Your TV is reflecting and your couch is absorbing. If you can put a first reflection absorber on the right (facing the system) you might find an interesting change. Use the mirror test and find the first reflection point, and during listening, put a portable panel -- there. Hide it away when you're not listening. A reasonable WAF compromise. Enjoy!