Crimea is actually a very soft target atm. A lot of the occupied territories are harder to fully breach than Crimea, unfortunate is that it comes with major soft targets, people. As Russian forces, there are in the middle of regular locals. It's safe to say that nobody from Ukranian side wants to kill any soft targets.Isn't Crimea an unrealistic target this year, for a number of reasons?
But they could cut it off, blow up the bridge and leave them to fend for themselves.