u110 in 41 provided a breakthrough in that it provided warning of 4 rotor naval Engima long before their introduction. It meant Bletchley had already started preparing for 4 rotor by the time it was introduced. It was the trigger for work on the 4 rotor bombes. There were other U boat captures.
American involvement is impossible to play down - convoys were critical to our survival, and there were tens of thousands of Americans based here for much of the war. I'm often just as disappointed when Hollywood plays fast and loose with mainly US operations like Guadalcanal or Midway. Even so Hollywood movies rarely attract the outcry U571 did at the time of release.
I just think we prefer to talk about the parts we played, just as any country would.
Gordon Welchman, another of the little known geniuses, moved to the US after the war to teach MIT's first computing course. He later worked on encryption for the US military. He wrote the Hut 6 Story in the 80s, the NSA didn't approve of his book, so he lost security clearance and was forbidden to talk about his own book or his involvement. There is a fascinating interview somewhere out there on the web, with some of his relatives, about him having a surveillance tail in his late seventies!
As another Engima related example, the film U-571 decides that presenting the real British capture of a U boat and its Engima machine won't do at all, so it was the Americans what did it. How else to perpetuate the Hollywood idea they win all wars single handed? ;)
Most of the history books after Nigel West's in the late 1980s cover the major Polish role in the story properly with more details. Until West, and the coverage after his book, histories essentially presented the official GCHQ authorised history. They omitted huge details, and enormously significant events and people like Tommy Flowers and Colossus remained almost completely unknown, even in Britain. A couple of Colossuses were sent to GCHQ at the end of the war, everything else was smashed to pieces and officially "forgotten about".
Which is why Tommy Flowers and others received little to no acknowledgement of their role during their lifetimes. Which is a fine way to thank people who played such a huge part in winning the war, and creating the post-war world.