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.
Except Trump doesn't have that kind of power.
The president has the power to not send more money to Ukraine. Trump will call Zelenskyy and say “we won’t be supporting you anymore, go negotiate”. The US has by far been the biggest donor to Ukraine so Ukraine would be in a tough position without that support. Worst case Ukraine tries to hold out but without US support Russia will mop them up, which is what Russia has been waiting for.
He can only do that if there is anyone else in the government that wants to do that. Otherwise he can probably be convinced not to.