So one principle you are not aware of is avoiding early reflections. You have the speakers too close to the rear wall and the cabinet. The rear wall will make them boomy. The wall and cabinet will mess with the frequency response and imaging. Usually about 2’ out from the rear wall is a good starting distance, and far from side walls. That’s one reason room treatments help. They can reduce these early reflections, and give you more placement flexibility, as can thick blackout curtains.
Your speakers are probably too far to produce a good image, but moving them in further with that cabinet is also not optimal because you are getting closer to those reflective surfaces. This is why I'm recommending you find out, at least as an experiment, how good your speakers can sound. The blanket is a test. Listen to my suggestions, see how good you can get it, and then that will help you decide what to fix.
Your speakers are probably too far to produce a good image, but moving them in further with that cabinet is also not optimal because you are getting closer to those reflective surfaces. This is why I'm recommending you find out, at least as an experiment, how good your speakers can sound. The blanket is a test. Listen to my suggestions, see how good you can get it, and then that will help you decide what to fix.