How Should the Ukraine War End?

From a New York Times column by Bret Stephens headlined “An Endgame for Ukraine”:

It may be that Ukraine’s long-awaited counteroffensive, which could be in its early stages, will be as fruitless as Russia’s winter offensive. Defenders typically have advantages over attackers in trench warfare, and the Russian Army has had months to dig in.

But it’s also possible that the Ukrainians could achieve breakthroughs that could put the end of the war in sight this year. What then? How should this end?