It would seem that the chances of the U.S. being attacked will be higher with Biden. Trump has worked toward energy independence, which requires a lot less fiddling with the politics of the Middle East. He also started getting the country out of Afghanistan, which Biden will probably reverse. I guess Iran is angrier at the U.S., but that’s because we aren’t sending plane loads of money over there anymore.
I doubt there is really any difference between how the two would manage an attack on America. Biden isn’t against war. He voted for the Iraq war, and the Patriot Act, he even doubled down on the war on drugs. He was part of an administration that had its fair share of drone strikes(even against American citizens without due process).