It doesn’t matter what Trump might threaten Ukraine with, they will never give up the land Russia has stolen from them, for to do so would make every Ukrainian soldiers death meaningless.
Russia however will eventually cave and give back most if not all of what they took with the possible exception of Crimea.
Russia is really the only one Trump would have any major ability to threaten. Ukraine does not have to have American money or equipment, when the rest of Europe is more than willing to help in that regards.
Russia will trade sanctions relief in exchange for currently-occupied Ukrainian territory.
Its going to be a complex peace talk and one that Trump will relish. In the end no one will be happy—but the war will stop and things rebuilt. Peace treaty by April—I predict. Signing in Minsk with Trump, Putin, Zelensky’s successor present, along with the new President of France and Nigel Farage of UK. But, war will still flair in the Middle East