This is an LCR "soundbar", not a "surroundbar". As such, it is just the front 3 speakers. It does not have any surround capability, nor does it bounce sound off the walls.
It will work acceptably in your niche, but it will work better if you move it as far forward as possible to reduce the influence of the niche on the sound.
Lombardi said it:
Perfection is not attainable, but if we chase perfection we can catch excellence."