If all American foreign policy just disappeared the world would be at a net positive overnight - and it's not even close.
3 years of us arming Ukraine, encouraging them to NOT negotiate (when they had much better position to previously than they do now), and then abandoning them once we finished dumping all our weapons. America was proud to fight to the last Ukrainian.
Russia is like the bullie that punches you in the face.
America is like the bullie that spends weeks pretending to be your friend just so they can steal your lunch money, humiliate you in front of your friends, and then push you into the other bullie that'll punch you in the face for bumping into them.
Also, Trump just puts a blunt face to what America has always been. Foreign wars in this country are bipartisan. Ukraine would be just as fucked if Harris was president. She'd just have a better narrative for it to make Americans feel less guilty for the fucked up way we treat our "allies".