1. Yes
2. No, but he did blow the pandemic response and make it worse though his desire to downplay it and by showing no leadership whatsoever RE mitigation measure; instead scoffing at mask wearing, business shutdowns....their call....and by holding super spreader rallies, as though that was just fine.
3. The resultant economic dislocation, because of his fucked up response, IS on him. And to that extent the supply chain problems, no less than the mounting Covid death toll, are on him.
4. What lack of enforcement at the border?
Did Mexico pay for a new wall?