I think it would end in a few months since right now Russian troops are withdrawing and no longer in hands of the Chernobyl. If a country enters the war, then there is a high chance that it would take years to end. If Russia does anything to other countries, maybe there would be a high chance of another World War.
I read from the news yesterday that the Russian troops may be reuniting to launch another heavy attack on the Ukrainian soil. Since the Russian president, Putin and is adversary had not reach an agreement, then I think the war may still continue. Although the Russian soldiers are lossing the battle which had led to lost of live of many Russian soldiers making them to retreat. I pray the war will stop soon cause with the way I'm seeing it, who knows what Putin has in mind.