The ground is static because the air is static, and the air is static because Russia’s air defense is not yet exhausted. When it is, Ukraine will be able to start flying a lot of planes, which will very quickly turn things around on the ground. We’ve seen what happens when NATO-quality forces with air superiority meet heavily-entrenched ground forces.
And Ukraine doesn’t have much to fill the power vacuum in the sea, but they don’t need much. All they need is something, anything, that can make it out to that bridge and finish it off. It could be a handful of explosive drone boats. It could be a few Special Forces guys in a raft. It could be anything. And once they do that, the battle for the sea becomes irrelevant because it will have been completely and decisively won by Ukraine.