If, in some wonderful alternate universe, I were elected President what would I do about the issues I am ignorant of? Does a President need to be an expert on everything? No, he doesn't. A President who is an "expert" often feels compelled to do something, even if it is not a good idea. It's similar to the saying about your only tool being a hammer causing you to see every problem as a nail.
The President needs to be able to call upon people who are experts to find out what they think. Then, and here is where all Presidents have so far failed monumentally, he needs to weigh the advice to see if it violates anyone's rights. If it does, don't do it. Next, he needs to think about whether the action falls under authority of any government, or specifically the federal government. If it does not, he should not do it. Last and rarely needed, he needs to make certain that the Constitution and Bill of Rights specifically allow the advised action. If not, don't do it.
If it sounds like this would result in a President who doesn't do much, you are right. That is the way it should be. A good President should do very little "governing". "He who governs least, governs best" only goes part way to the truth: "He who governs only himself, governs best". It is time for a President who only truly governs himself, and does his best to keep the rest of the government contained, and then gets out of the way of the rest of us to do the same.