So long as Ukraine remains a chew-toy tug o' war rope between east and west this is going to flare up from time to time, and the only long-term solution is to remove it from play.
We need to enforce a muscular neutrality on Ukraine. I am not calling for Putin to be able to get in there and install another puppet. A truly neutral Ukraine with UN troops on the ground and observing the elections if necessary. Instead of forcing Russia to pay for reparations, we make that optional for them, even as we go in full bore with a Marshall Plan 2. While Russia tumps over their vodka-sodden couch trying to scrounge a few stray kopecks, the west is out there rebuilding the country and handing out candy, flowers, and construction contracts.
And again, we make Kyiv a banking center to rival or surpass London. Ukraine becomes a giant Switzerland with worse chocolate but hotter women.
We let Vlad keep Crimea and those little provinces over there so he can claim a grand victory while our sanctions drag on and on and more and more people figure out what a shitheel he is. CIA, MI-5 and all the other western intelligence agencies are working on the oligarchs...
Or we can act rashly on the contigencies of the moment and possibly spiral all out into nuclear war.