Two mains issues, and yes they are very common. The first is the square room, and you're just scrooed there. Oh well. The second is that because the space is modest, you are given little to no freedom in bringing the speakers out (if the SBIR might demand that) and that you yourself are right against the back wall.
So, YMMV, but you can try treating the hell out of the place. How far are you willing to go? You will still have issues, but more is better for sure here, broadband, every corner if you can, and yes that means all 8 "tri-corners", and every other meeting of boundaries. Yes, that's nuts, insane, and maybe no one does that. Just getting a point across.
A thought I have, if only for the moment, is to completely forget all aesthetic and ergonomic sensibilities, and place the speakers and yourself for the best sound, period. I will absolutely guarantee that this positioning will impinge on your happiness and lifestyle. What I then recommend is that you mark these positions, so that you can place the speakers and yourself in this position for when it's time for critical listening, and not so much for background fill.
