The long wall is usually a good place for the speakers in a room such as yours. I have a similar situation but in reverse (if I’m reading your post correctly) whereas I can’t use the short wall due to asthetics and such and the fact that there is a wood covered Lally column separating the room. I find the system just so happens to sound better this way in my room. I might add that the room is fully finished in drywall, and fully carpeted, with a gigantic sectional couch and countless throws, pillows and blankets. There is no wall on the right side, open to rest of the room. It’s a pretty good mix of absorptive and reflective materials. Still working on a few diy treatments...the only thing I can recommend to you is maybe pull those speakers closer together by about a foot...and tow them in so that the axis of both speakers crosses just in front of you at your listening position. It may or may not improve Soundstage and central image. I use Tannoys and they are big proponents on serious toe in. A more radical toe in will decrease the effect of room boundaries to a degree.