My uncle was a “Frogman” UDT in the Pacfic during WWII. Wanted information on his service as he passed in 1971. The Navy Seal / UDT museum in Ft Pierce Florida was helpful. Was able to identify the UDT team he was on and also was able to get a copy of his Bronze Star citation from the invasion of Guam from the US Navy archives. A unit history of his team also.
Another Uncle was an Air Corps pilot and was killed in a crash flying out of Pope Field at Fort Bragg in 1943. Family never knew the full details. I contacted the Air Force Archivist at Maxwell AF base in Alabama. The AF crash records through the 1950s had been declassified and she sent me copies of the crash investigation report and pictures of crash site.
Just keep trying other sources, sometimes you get lucky. Unit numbers, dates of service, places served etc can help you piece together the story.
Good luck.