ATACMS is old missile with poor accuracy. Each HIMARS can only shoot 1 missile. They would need to shoot a dozen missiles to be able to hit Kerch bridge at 300 km distance. The more distance, the less accuracy. Bridges are hard to disable and easy to repair. Now that the land route to Crimea via Donetsk, Zaporizia, Kherson oblasts is complete, disabling Kerch bridge for a couple of weeks serves no strategic value other than pissing off entire Russian nation and escalating the war. I wouldn't be surprised if Kiev dam becomes a target if Kiev regime chooses to disable Kerch bridge or a couple of weeks.