He promised to end the Ukraine war in one day.
He didn't say which day that would be...
Anyone can issue executive orders. EOs can easily be overturned by a future president on a whim. EOs are neither transformative nor lasting.
No, only the President can issue executive orders... Well, unless it's the Biden administration then any intern close to the President can because Biden is senile. Executive orders can be "transformative" and last. For example:
EO 9981 ended segregation in the military.
EO 8807 created the Manhattan Project.
EO 10730 Led to public school desegregation
EO 13228 Established the Department of Homeland Security
The Emancipation Proclamation was an executive order
I'd like to see any of those overturned on "a whim."
A lasting presidential legacy is the result of getting a substantial legislative agenda passed through congress. Trump was too incompetent and lazy to have any significant legislation passed in his first term except for a tax bill that mostly benefited venture capitalists and billionaires.
This is largely bullshit too. A lasting presidential legacy is built on a President doing important stuff domestically and internationally that has significant impact. Negotiating a significant treaty, conducting a successful outcome in war, or having a positive and lasting impact on society domestically are things that Presidents are remembered for.
I think one of the significant things Trump did in his first term was get many Arab states to establish diplomatic relations with and enter into treaties with Israel. On the legislative front, getting rid of the "tax" penalty in Obamacare was significant as it ended the one thing in Obamacare that gave that legislation teeth. It rendered Obamacare largely insignificant.
Trump, also by executive order, created the Space Force. What significance that will have is yet to be seen, but it isn't going away anytime soon and it will have significance down the road.