His entire trade war with Canada and Mexico started because he thought the current trade deal (The USMCA) was a horrible deal that should have never been signed.
He's the one who signed it. The USMCA was his creation because he wanted NAFTA replaced.
Narcissists can't accept anything they don't create as legitimate. When you factor in dementia, that's a very dissatisfied narcissist. When you make him leader of the free world, that's a very unhappy world.