Mysterio fits all of that.

He was screwed over ruthlessly by a Tony Stark who wasn't in his right mind due to feeling guilty about Ultron. Quinten Beck didn't deserve to see his life work destroyed and him being fired and called unstable.

His intentions were good to get revenge by becoming even more popular and beloved hero than Iron Man.

Realistically he's the hero of his story by taking all his anger and feelings of betrayel and choosing to turn them into something positive and also including other people who were similarly betrayed by Tony to become heros and devotion the rest of lifes to be a Superhero and help people.

His Method's are bad however because he could have simply used his drone's to a superhero and openly letting the world know he's was simply using technology like Iron man and simply wait for a real villain to come like every other hero and actually stop them. instead of making up a bullshit story and actually creating villains to fight that were also killing people just so he could he a hero.