For explanations of the scope of permissible Torah study for Noahides, see The Divine Code, Chapter 5 - with the footnotes and editor's notes. As explained there, a faithful and observant Noahide is allowed to read Mishneh Torah by Rambam (Maimonides), on a straightforward level, in the parts that are related to observance of the Noahide Code. He can also read the parts that are related to the logical Jewish commandments which Noahides can perform as righteous and upright actions (but not as spiritual statutes) - for example, honoring parents, returning lost objects, and giving charity.
On the other hand, if you want to know and understand the details of what things are permitted and forbidden specifically for Noahides to observe, you need to study The Divine Code by Rabbi Moshe Weiner: https://asknoah.org/books/the-divine-code
On the other hand, if you want to know and understand the details of what things are permitted and forbidden specifically for Noahides to observe, you need to study The Divine Code by Rabbi Moshe Weiner: https://asknoah.org/books/the-divine-code