I agree with the first part and simultaneously disagree. It’s weird. The disagreement is in that most of what Maddie did in Inferno are things Jean herself would not have done if she went through what Maddie went through. It’s the nature and nurture type thing. By nature, Maddie was like any normal woman with dreams of a family with her true love, like Jean was. She had a fiery temper and was a fighter through an through even with stacked odds. She was nurtured to insanity after realizing her life was not real. We know exactly how much Jean Grey values her agency over her life. Wanting things as perfect as she can manage in her power. I am positive if Jean had suddenly found out that someone had been running her life the way Sinister did to Maddie, she would spiral into destructive territory where she would do everything she can to get to a place where in her mind she has reasserted control, even to the point of breaking off connections she had once had,
I also agree that Maddie is a different person in the respects that she had a different life from Jean. She had no powers of her own, her pessimistic viewpoint was shaped through different experiences, and she has even said that she is the dark side Jean would never dare to wander. That in turn makes a very, very fine line between her and Jean being the same person, but it’s a line nonetheless that exists to separate them.
As for the second part of about Maddie getting a life, that will have to come way, way later. You can’t establish a motivation for someone and suddenly abandon it. Maddie has a grudge towards people on Krakoa and it shouldn’t suddenly go away because they welcome her in. Madelyne isn’t a healthy person. She is driven by her hatred and desire for the agency in her life that Jean has, and thus has a jealousy towards what Jean has. It’s why Maddie has on multiple occasions attempted to replace Jean. In her mind, if Jean was out of the picture, the one person who she is modeled after wouldn’t exist anymore to color people’s perspective of her.