One thing which is basically hard evidence. The radio operator on a U.S. Navy ship, I think it was the Itasca, heard her very near and very strong radio signal.
This was shortly before they lost contact. She had to have gone down close to it.
Long analysis of Earhart’s radio signals:
https://tighar.org/Projects/Earhart/Archives/Research/ResearchPapers/Brandenburg/signalcatalog.html