I have little trust that an "end" that leaves Russia occupying a large portion of Ukraine will last. It's a message to Russia's leadership that invasions will be rewarded. First Georgia, then Crimea, then Ukraine more broadly. Make some allegations about a Russian minority being persecuted and it's time to roll in the tanks! That's probably a large reason why Europe has been willing to arm Ukraine to the teeth: to send a message that the West is serious this time after wimping out in the case of Georgia and Crimea.