There is nothing Zelenskyy could ever do to help his case with Trump, since Trump is already "дело верное" for Putin, but I would say that Zelenskyy's decision to publicly snipe back at Trump put Trump off track and caused him to lash out, which hurts Putin's efforts to get the American people on Russia's side, or at least to forget about Ukraine. Trump is more openly exposing himself as Putin's stooge, and people are pushing back against that, which we've been seeing in these Republican town hall videos. So, Andrew Kramer of the Times, to the degree that the Trump regime is responsive to US public opinion, seems to me what Zelenskyy is doing might actually help Ukraine.