Is a wife permitted to leave the marital home because her husband did not adhere to his promises before marriage, due to her mother-in-law's excessive interference in their lives, and his refusal to bear her financial and educational responsibilities, and to what extent would Allah be displeased with her for doing so?

You have the right to refuse to live with your husband's mother and to leave the house until your husband provides independent accommodation, because you stipulated this and due to the harm you mentioned. Your husband must also fulfill his promise regarding your studies. It is advisable to try to reconcile with your husband by compromising on some conditions if they do not cause harm, and to be patient with his mother and treat her kindly to honor your husband, while thinking well of her, as Allah Almighty says: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin."