It’s levelI agree about removing some of the image on the right side where the bright background pulls the viewer's eyes away from the prime subject.
I do not go much by the rule of thirds but I will draw an imaginary line from an upper corner diagonally to the opposite lower corner. Often as not the placement of the subject along this line makes for the strongest image.
When I first looked at the image on my screen the first thought I had was that it needed a Levels adjustment.