The way for Ukraine to have total victory in this war is for Putin to be overthrown. An almost sure fire way to get that to happen: Ukraine takes back Crimea. A defeat on that scale would almost certainly be the end of Putin. Even his iron grip on power could not withstand a humiliation like that.

And that appears to be Ukraine's strategy. Their medium range drones are cutting off land supply routes to Russia's forces in Crimea (and everywhere else on the front). Drone and missile operations have also forced the Russian Navy to reduce its operational footprint in the northwestern Black Sea, making resupply of Crimea by sea untenable. The next key would be destroying the Kerch Bridge. It remains partially functioning for both vehicle and limited railway traffic, although with restricted capacity due to past attacks. If it is destroyed entirely and other routes are unusable due to drone attacks, Crimea would be so isolated it would be logistically and strategically untenable for Ruskie forces to remain.

That would be the only real path as Ukraine lacks the amphibious and mechanized forces required to launch a successful ground invasion of Crimea. Choking off the peninsula is the way to systematically demilitarize it. If Ruskie forces there collapse, Ukrainian forces could possibly just walk in.