If the ONLY thing Trump does is impose “don’t spend it if we don’t have it” (which the Executive CAN impose), that will make an enormous positive difference. (And probably start The Great EBT Revolt, but I’m ok with that.)
Beginning with Th. Jefferson, presidents impounded funds appropriated by Congress. This process came to an end with Richard Nixon. In 1974 Congress passed the Congressional Budget Impoundment and Control Act of 1974. Since that time no President has lawfully been able to impound spending. This explains the explosive growth in the deficit and national debt since the mid-1970s.