Some years ago a student came to me in anguish, confessing that he intended to convert from his Protestantism to Roman Catholicism. He was in anguish because, of course, this would cause some consternation, if not disruption, within his family and among his friends. I asked him why he planned to convert and he said “Because I need someone else to tell me what is true.” He clearly meant (and said) he wanted the pope to decide truth for him. First, with tongue in cheek, I offered to be his desired arbiter, decider, of truth. He declined my offer. Second, I pointed out to him that by deciding to convert he was deciding for himself what to believe about truth. He had not thought of that.
Although this stands on its own two feet, it's worth making some additional points:
i) What's the goal? Is it to avoid believing falsehoods? But suppose the institution you choose to tell you what's true is unreliable? If the Roman Magisterium or Eastern Orthodox tradition is not a reliable arbiter of truth, then there's certainly no presumption that you will believe fewer falsehoods. If you rely on someone else to tell you what's true, and you pick the wrong horse, you can easily end up believing more falsehoods that if you use your own judgment.
ii) What makes some people think they have the right to contract out their beliefs to a second party? What if you are directly answerable to God for what you believe? What if God takes a dim view of people who give a religious institution a blank check? What if God didn't authorize you to delegate those decisions to someone else?
iii) Joining the church of Rome or the Orthodox church is not an alternative to denominationalism. Rather, you've decided to join the Roman Catholic denomination or the Eastern Orthodox denomination.
iv) Even if, hypothetically, the idea of a magisterium sounds preferable, if the actual candidate is demonstrably unreliable, then that's a nonstarter.
v) Does God hold you accountable for having false beliefs, or does God hold you accountable for why you believe it? Suppose you make a good faith effort to believe what's true. Will God condemn you if you made an innocent mistake? If you made the most of your limited opportunities, but failed to get it right, is that culpable? Is that what God cares about? Or was the fact that you were conscientious, that you did the best you could given your natural aptitude and the available evidence, praiseworthy even if you happen to be in error? How does Scripture prioritize our duties? For instance: Love God with all the heart and with all the understanding and with all the strength, and to love one’s neighbor as oneself, is much more than all whole burnt offerings and sacrifices (Mk 12:33). Here the key consideration is the motivation.