I’ve read that the Rosenbergs were actually doing Submarine Espionage. The Soviets offered them up as a decoy because the Intelligence agencies were getting to close to the real atomic spies.
“...actually doing submarine espionage.” You have fallen for a disinformation propaganda piece if you believe that.
They were in at the beginning on Soviet KGB and GRU spying on the Manhattan Project. Multiple books, including by Soviet defectors and the Venona Project have verified their treason. See these articles:
https://www.historynet.com/the-venona-project.htm
https://www.osti.gov/opennet/manhattan-project-history/Events/1945-present/venona.htm
Or read this excellent account:
The Venona Secrets: Exposing Soviet Espionage and America’s Traitors (Cold War Classics), by Herbert Romerstein and Eric Breindel | Oct 1, 2001