The ATACMS should have the same problem with bridges as M270/HIMARS and SCALP/Storm Shadow. They hit the road surface, punch a hole and the explosions happens below in the open.

It might be the best if Ukraine continues their efforts with their own developments e.g. via water, as they can easily damage the pillars and foundation of the bridge. Or even lift and destroy a whole bridge segment between two pillars, as we have seen in the past.

The ATACMS will certainly be of big use for storages and hubs far behind the front lines. But as the article writes: "It could be months before Ukraine receives the missiles, according to the official."

Besides ATACMS delivery, the USA will also have to maintain their HIMARS launcher, as they were altered before delivery to be unable to launch ATACMS (source: https://www.wsj.com/articles/u-s-altered-himars-rocket-launchers-to-keep-ukraine-from-firing-missiles-into-russia-11670214338). But maybe a simple software update can be installed? There were no details mentioned how the launchers were modified.