In Days of Future Past, Charles had already opened the school before the movie begins, but had closed it in light of the Vietnam War that drafted a good number of his older students and faculty. The constant losses in both his advocacy and personal life led him to depression for a few years before future Logan arrived, but after fighting alongside Logan and Erik and meeting his alternate future self, he regains his spirit, forgives Erik for the accident, and reopens the school to new students.
In the time between Days of Future Past and Apocalypse he would come to reach out and recruit many students, including Jean Grey. She would be one of his first and oldest students (as per the flashback when he comes to get her as a child), promising to help her control her powers and find a home within the school.
Additionally, future Charles tells past Charles that "Just because someone stumbles and loses their path, doesn't mean they're lost forever." This becomes a repeating theme for him for the rest of the films, from directly disobeying En Sabah Nur to encourage the literal world to fight for and protect those who cannot fight, to drawing Jean back to herself at the risk of his own his life.
On a more personal note, Charles consistently appeals to Erik to find kindness for the humans across all four movies, and offers him emotional support after his family were killed in Apocalypse. Charles also appeals for kindness with Raven; in Days of Future Past, he asks her to rethink murdering President Nixon when there is still hope for human-mutant cooperation, if not equality.
Negative Traits: Arrogance.
Charles' arrogance is often well-meaning but it doesn't excuse the way he presumes to know what's best for others. He constantly undermines Raven's desire for recognition, for instance, downplaying her disappointment in feeling inadequate because of what she sees are her undesirable mutant features.
In First Class, he outright dismisses her concerns after a night out to town, berating Raven for not being subtle about her mutations in the presence of humans, claiming it would not do her any good. However, Charles also claims that mutants should be proud of their abilities and how they can be helpful in achieving peace with humans, recklessly revealing his own abilities to the CIA and putting Raven in a position to reveal herself in Charles' defence.
Negative Trait: Manipulation.
Charles has very few compunctions about using his abilities to manipulate people. He has no problem barging into the CIA directors' minds to dig up memories, freeze them in place, or even coerce them to follow his lead; he even goes as far as erasing entire memories from people's minds, like he does with Moira McTaggert in First Class and a young Jean Grey immediately after Days of Future Past, with the latter catalysing the events in Dark Phoenix.
Negative Traits: Hypocrisy.
Charles spends much of Days of Future Past reclaiming his moral fortitude, as the movie showcases just how privileged and hypocritical his perspective has been regarding mutanthood and how he applies his idealogies to himself and others.
In the movie, Erik Lensherr calls Charles out on hiding from the world when it needed someone like him to stand up for other mutants. Charles has always claimed to be proud of what mutants can do for mankind and how they are the next step in the evolutionary ladder. But in the ten years since the Cuba incident, Charles has relied on a serum to lock away his powers to manage his depression (he's essentially lost his sister, best friend, colleagues, and students in the past decade) and unaddressed trauma.
Erik unfairly but correctly accuses Charles of hiding from his pain while other mutants who he could've helped were in similar states or worse, and are unable to do what Charles has done for himself — to which Charles answers that he takes the serum so he could shut the voices out and not feel their pain bearing down on his mind.
revisions.