Here is the Pareto Optimum from Putin's War.

1. Give Putin a piece of Ukraine (the part that is closest to being Russian on its own right).  I don't know what that is, but surely Zewlensky and Putin know what that is.  

2. Ukraine gets its freedom to be recognized as an independent sovereign state by Russia.  Ukraine gets to join the European Union.  Ukraine gets the support of the free world in its defense and its rebuilding.  Ukraine has complete access to the sea from barnyard to shipyard and the right to ship its goods around the world.

3. Europe gets another country in its Union.  Europe is already getting Sweden and Finland added to NATO.  Europe should enjoy the fact that it showed unity during this period, plus the fact that reaffirmed that the U.S. is a key ally.

4. United States gets a recognized leadership role to implement globanomimcs.

5. As far as all the others, China, India, Africa, South America, etc. they get a world at peace and an economic framework where everyone tries to help everyone else out.

Sure you can find things that i left out, or did not think about, but so what--just figure out how to incorporate those things into a "lasting peace" and away from war.