Torah from Merav to the student

Does someone who studied Torah alone sit and study all of Shas and Rambam and the Beit Yosef Shulchan Arba with all of the Nok and all of the Chazo’a word for word, and his mind is mixed with the people’s, and he is extremely wise, but he has never studied with a rabbi and has not discussed Torah issues with a group or students? Does he simply sit and study? Can he also be tested on all of the things he has learned and receive a hundred? Is there something he lacks? Can it be said that he will rule on halakha and say sabbaths incorrectly? Is there something fundamental that passes through speech and life near the great and that it is impossible or very, very difficult to get him to simply learn everything that is written?
Thank you very much for the explanation.