Donald Trump is not a politician, nor is he smart. He knows business and better yet he knows how to be a crooked businessman. He's not very good because his ventures eventually fail. His empire consists of a reality TV series with an idiotic tagline, "You're fired", and a string of ex-eastern European models who were his past and present wives. He has no understanding of how the system really works he is just play acting for the idiotic American public who are borderline racist to get where he wants to be, in the limelight. He is controlled by the one percent and is being groomed to be the next Ronald Reagan with a dash of Adolf Hitler sprinkled on him to put this country on the fast track to the road to ruin. Trump probably hasn't even read the Constitution.
I don't think Trump knows or cares that a lot of his ideas are unconstitutional. He's so egotistical that he thinks he is more important than the Constitution, or any laws. When challenged and informed that he is attempting to do unconstitutional things, he will respond with petty insults and weak, tangentially related arguments.
Trump isn't close to an expert on the Constitution; in fact he hasn't really mentioned anything about it other than referencing the Second Amendment as all Republicans do. He's also not notorious for vetting his ideas, so he's usually speaking off the cuff. There's no way he even can keep track of everything he said, let alone its constitutionality.
All evidence suggests that Trump is deliusional and he either does not know or does not care. He has a tendancg to say whatever he thinks will make him sound better or win the argument right now, even if it is not based in reality. He does not seemed concerned about the consequences.