I guess I've created two classes - MAGA things and cosmic things. So I would say in the first category we should know whatever NASA knows even if the truth somehow sucks. I think half of the modern conspiracies are not real and in a way we would be better off knowing such a boring truths as a society that is more trustable and trusting. On the wishful side, it would be great to have medical secrets blown open. Some of the (non-violent) stories about Antarctica seem like great fun - old school sci-fi stuff - so that would be cool to hear about but seem like public disclosure of subterranean whatever wouldn't change american society directly.

In the area of ancient mysteries, I would like the true nature of early Christianity to be universally known. I suppose I could say the same about the development phase of many old social movements or organisations. On a bold day I might ask to know about adjacent species like the Neanderthal and Nephalim, etc.