The Ukrainian military has no chance of a successful military push to recapture Kherson, much less Crimea. These are desperate fantasies put out by Kiev to try to keep western interest and support for as long as possible. Russia will never allow Crimea to be retaken and the Crimeans themsleves would fight viciously to resist going back under Ukrainian rule. I know because I went to Crimea in 2015 and talked to a cross-section of Crimeans.