What is the ruling regarding a woman who married without a guardian (wali), then grew to dislike her husband and adopted the view of the majority scholars concerning the invalidity of the marriage, because it aligns with her desires? And is she considered married?

The preponderant opinion is that marriage without a guardian (wali) is null and void (batil and fasid). Annulment (faskh) or divorce (talaq) would be the means of separation between the spouses. If the husband does not divorce her, she must refer the matter to the Sharia judge. It is not permissible for her to leave him without an annulment or divorce. It is not permissible for a Muslim to pick and choose among the opinions of jurists according to his whims; rather, he must consult a scholar whom he trusts.