Attrition usually favors one side or the other, but it's not always clear which until after the fact. The only thing that's certain about the official numbers on both sides is that they're lies. Estimates from neutral sources vary widely.
Ukraine is likely in for a bad time if Trump wins. They need materiel to prosecute the war, it takes the United States to supply a war machine of this magnitude, and Trump seems likely to turn the spigot off, whether by act of Congress or the veto. Your guess is as good as mine what happens in November. I still don't like the polling data series, but even the polls most determined to shove people into a box are coming up with five percent undecided, and a dead heat at the national level. If the undecideds break toward Biden, he can win.
China is being cagey about how they support Putin, but it's hard to see them concluding that abandoning him entirely is in their interest. I wouldn't expect Putin to run out of ordinance, but I wouldn't expect the PRC to render him flush with it either. Their interests are best served by a Pyrrhic Russian victory, and they want to dodge sanctions from the West insofar as it's possible.
Both sides are struggling to find troops. Putin is turning out women's prisons. Zelenskyy has conscription squads roaming the streets looking for draft dodgers who have gone into hiding. Russian cruelty has kept morale up among those under arms in Ukraine, but they're running out of willing (enough) participants.
If political leadership on both sides knew the truth of the situation, they would probably come to the conference table, but they don't. There's ample reason for both sides to think all they have to do is keep doing what they're doing, and that the opponent will break first. The one thing I think we do know is that when the end comes, it will be much like World War I, or the US Civil War. It will happen fast.
