Trump just wants the war to end. Ukraine doesn't want to surrender a chunk of its territory under bad terms, so they won't make a deal. Putin is more than happy to take a deal that means they win. Trump thinks that if he weakens Ukraine then they'll be more willing to take a bad deal. He also doesn't like Ukraine or Zelenskyy, so has no particular desire to do them a favour.
Ukraine already surrendered chunk of its territory few years ago. You think this time it will be different and Russia won't try to take Ukraine again once it rebuilds its military potential?
