My solution to Ukraine is 1. Ukraine vows to not join NATO 2. Ukraine accepts Donbas area previously (before Feb 24, 2022) as part of Russia. 3. Ukraine accepts Crimea as part of Russia. 4. All Russian forces immediate withdrawal from Ukraine identified in 2 & 3 above. 5. NATO promises not to allow Ukraine membership. 6. Russia vows never to invade Ukraine again. 7. All sanctions and arm sales go back to Ante Bellum status. I have no doubt that some version of your "solution" will eventually prevail. It sure looks like we'll have some sort of divided Ukraine, akin to E vs W Germany or N vs S Korea. The BIG problem, of course, is who/what institution will "enforce" all of the promises?
Actually, the Donbass region (that is/was in separatists' hands, not all of Donetsk and Luhansk--see map in gray) and Crimea aren't really a huge chunk of Ukraine.
I think that only after a generation since the Soviet Union broke up, they'd have some form of border adjustments based on local popular determination.
Ukraine was trying to force the Donbas Russians to remain in the Ukraine. That has been one of the main rough points between them and the Russians.