How can one reconcile pleasing Allah and abandoning a conversation with a young man she is attached to, with the desire to marry him lawfully, while fearing falling into the unlawful or that the marriage will not be blessed?

The conversation between you two is impermissible, whether in Ramadan or at other times, because the young man is a stranger to you. You must repent from this relationship. There is no blame in your heart becoming attached to him, as it is an involuntary matter, but you must avoid forbidden acts because of it. If he is a man of religion and good character, you may propose marriage to him. If he refuses, cut off all ties with him and turn to Allah. Marriages based on online acquaintances often fail, but sincere repentance elevates previous prohibitions. Sins may be a cause for preventing good or bringing about evil, but this is not necessarily the case.