I’m not sure Ukraine wants to destroy the bridge. Rather just damage it enough so only light transport can use it. If they attack Crimea they would probably prefer that the civilian population loyal to Russia and escape across it and not stick around to need food, water, and medical care supplied by Ukraine. The big question I have is whether Ukraine has some means of destroying the big ferries if the Russians try to bring in heavy weapons—HIMARS or something sea borne?
First things first: That bridge needs to go. It is not just heavy trucks laden with artillery ammo that bring important military equipment. Smart light weapons, upgraded electronic warfare equipment, and personnel are crossing that bridge. It is time to break some eggs…
If US ATACMS destroys Kerch, that may "provoke" Putin more somehow, as if spending a decade building up to invade, then invading Ukraine was not provocative enough. Russia air defenses and operations around Crimea need to get worn down first. Kerch is operating at significantly reduced capacity, that is good enough for now.
As for destroying the bridge the first time Russia says it was truck bomb, which doesn't make sense since all trucks going over the bridge are searched and x-rayed. One alternative explanation was Ukraine used some kind of seaborne drone to attack the bridge. Except their known sea drones look too small, even if a dozen were used. Despite official explanations or non-explanations, How Kerch really was attacked is still a unanswered question.
Ukraine's sea drones, Neptune anti-ship missiles, and the remaining Bayraktars are why Russia's navy has been locked up in Servastapol. Operator Starsky reported a sizable Russian naval force put to sea yesterday. We will know in a day or two what the current naval situation is.