But that’s the thing, he wants to overthrow Palpatine to regain the power and status he lost. After the Force memory his mother sent of his father, he grows to no longer need that. But it was still his goal throughout the beginning of the film.
Destroying his mask was a symbol of autonomy, relying on himself, free from bondage or trying to free himself. The mask was a symbol of him being trapped in his desires to have control. He takes control when he destroys the mask, and he realises he does not have control when he remakes it. When he takes the mask of throughout IX, it’s to take control of a situation.