The force from walking and shoes that produce bunions is substantial and ongoing. The question then, can exercises fix bunions by overcoming that force? The answer is probably ‘no’ unless there is a change in those forces that re producing the bunion in the first place.
That does not mean that exercises should not be done. Even if exercises are not capable of correcting a bunion, the bunion exercises may be very helpful at improving the pain that might be present inside the joint.
The best exercise is probably the one in the image about using a toe straightener belt or something similar that helps pull the toe into a straighter positions. It will not fix that alignment problem of the toe, but it will keep the toe mobile and flexible and help with any symptoms coming from arthritis like problems deep inside the joint. That has to be a good thing.