Well, to begin with, I hear this question from plenty of in-married families too. So you should know you have lots of company in this particular moment. Because of the model Chabad uses on campus, and because college is a time of exploration and searching, this happens with plenty of students.
The single most important thing to remember is that you want to keep lines of real communication open. Your daughter is an adult now, and she gets to make these choices for herself. As an adult, she’s far likelier to listen to you, and respect your questions and suggestions, if she feels like you’re listening and respecting.
So do explore alongside her. Go to Shabbat dinner with her on a campus visit. Ask what she’s reading. Engage in an open way. Treat her as an equal and in doing so, remind her that she wants and deserves to be treated as an equal. Suggest she take Jewish studies classes. Encourage this interest in ways you support, rather than making this a battle.
One other suggestion: maybe offer to help her get to Israel if she’ll consider a more egalitarian program. Look into non-orthodox (but serious study-based) opportunities. She may only have experienced Chabad in this way, but there are plenty of non-denominational ways to learn deeply about Judaism, especially in Israel. I’d venture to guess that (or something like it) would be fulfilling for her in the same way, and more easily integrated into other aspects of her life.