I have read several shojo manga as a teen that now as an adult make me go "... problematic 😬". The manga on this list I can enjoy and recommend as an adult. While there's usually a romance (or several), there's also deeper themes such as absent parents and grief - check CWs just in case. You're welcome to leave recs in the comments! (I will read them before I add them, so it might take time, but I will check out anything you throw at me.)