The Prez can declassify almost anything, and Congress has no say in the matter.
There are certain subjects, like nuclear weapons, that are in a different category. “Restricted Data” cannot be declassified, by statute.
Explainer below.
Link: https://twitter.com/wellerstein/status/1558069945820483590?s=21&t=HfHF5lt4K1tgOS0qEyde8Q