What would’ve happened if Harry Potter killed Umbridge?

So it’s no secret that Dolores Umbridge is one of the most hated fictional characters of all time if not the most hated. Even more so than the franchise’s main antagonist Voldemort. She took over Hogwarts and tried to make it into her own image just to get rid of the bruises on her ego. And I’m pretty sure Harry was doing everything he could not to point his wand at her and say Avada Kedavra. But what if he had done that. What would’ve happened
What would’ve happened if Harry Potter killed Umbridge?
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