Rambam says that one who does not believe even one of the 13 principles of faith does not get into Olam HaBa.
Here is my question: The same Rambam spoke about the concept of a Tinok shenishba bein hanachrim; supposedly this person is forgiven for not following the halacha. Supposing that person knows a lot of Jewish opinions (including Karaite and Christian opinions) and a lot about Torah, etc. and keeps studying them, but they continue to sin because it's convenient to remain as they are and they don't have enough evidence to change there whole lifestyle. Is there a chance they have stopped having the status of Tinok shenishba bein hanachrim? Do they still get forgive and admitted into Olam HaBa?