It seems like there's no way that Biden can make any negotiation with Russia seem like a win to his base so if he wins it's almost an automatic 4 more years of war. But if Trump wins he could make most of the concessions that Russia wants and still sell it as "the best deal" to his fans. Is a trump win the best hope for shortening war?
Disclaimer: I would never vote for trump, I also won't vote for Biden, I'm also in a state that always goes one way so it doesn't matter at all.
I'm going to go against everyone else and say that neither Biden nor Trump can end the war. Trump can cut the US support, but that's all he can do, and even if that led to Russia regaining the momentum, it won't win, in the same way that Bush's MISSION ACCOMPLISHED banner wasn't the end of the War in Iraq.
At most, what can happen is that the Ukranian side of the war turns into an insurgency, and we love saving lives through counterinsurgency don't we folks?