Based on both his boasts about his own greatness and achievements, and his complaints about how he's being treated, it's fair to say he wouldn't stand a chance of passing even an elementary school history test. Obviously some of that would be deliberately grandiose boasts, but I find it hard to believe that all of it is just an act - there's far too many testimonies from people who've interacted with him, including his allies and administration officials, that make clear he's not really different in private. And let's just say that statements like how most people don't know that Lincoln was a Republican, as if this was something he had cleverly discovered despite attempts to hush it up, aren't exactly inspiring any confidence in his knowledge, either. Or really any other statement he has made about Lincoln, and there are plenty of those. Similar thing with the rather hilarious 'nobody knew health care could be so complicated'.
Then there's his belief in ridiculous conspiracy theories, such as the one about how the Chinese 'invented' global warming in order to undermine American manufacturing. There's the endlessly repeated nonsense about how the Chinese are the ones paying the tariffs the US imposes tariffs on their goods, or how the trade deficit means that the Chinese are stealing from the US - trade is one of his favourite topics and yet a huge share of what he says about it is factually nonsensical.
Being ignorant may not be a disqualifying factor for the presidency by itself - not in Trump and not in AOC either. But being too lazy and uninterested to learn the things you don't know, not bothering to listen to or read briefings, endlessly repeating nonsense when you've been told about your errors again and again, and last but not least bringing every discussion on every possible topic back to yourself, your ego, your poll numbers - that is disqualifying, or should be anyway. I'm not aware of AOC having any of those flaws, though frankly I don't care enough about her to know that much about her. As far as I'm concerned she hasn't done anything to remotely deserve the hype.
And did you read the Pelosi letter I referred to? Even if you think impeachment is uncalled for, it reads like the ravings of a madman - the Salem witch trials comparison is getting a lot of attention but although that may be the most bizarre bit, it's far from the scariest. I would've liked seeing a longer rant about the Salem witch trials than the one throwaway reference, though, that would've been comedy gold.
Speaking of comedy gold, one Republican representative just went one further and said even Jesus was treated fairer than Trump - I'd like to think he was intentionally being funny, but I'm afraid it may have been accidental.