Can you be saved living in sin

I want to first preface that I do not mean this as an argument whether or not these things are sinful, nor is this an attack of people who think they aren’t. Fore the sake of the discussion I want to just assume that things such as abortion, and homosexuality is a sin.(again not arguing whether or not they actually are or aren’t) let’s say that there is a person who is pro choice, and affirms that homosexuality is not a sin. They have arrived to both of these conclusions, because they have studied the text, and genuinely believe that it isn’t sinful, after doing research on the subject, have arrived at the decision, in trying to find the truth. They wholeheartedly don’t believe that God condemns these behaviors. If this person has arrived to these conclusions in good faith in trying to be truthful to God, and they live out a life of repentance, they are trying to be faithful to God, will God eternally damn them, even though that person believed they were following what God commanded? If God does eternally damn them, this would then seem to me that God would punish someone for eternity, after putting their faith in Christ, based off of an intellectual mistake.