Would the government be able to destroy all evidence so that we never know anything?

One of my biggest fears regarding the subject is… never knowing the truth in detail regarding this phenomenon.

I have always thought that if one day everything is declassified, the government will eventually destroy or cover up some shit that is no convenient for us to know about.

Maybe we could finally have the official revelation that they are on our planet, that we have technology and extraterrestrial bodies and some other more gruesome details.

But never perhaps the communications or dealings made with them (if there are any) nor the darker details of the whole matter. Companies only care about their technology and the money that can be made with it, however it is the government that is in charge of the true intentions of the NHI, and that is what is worrying for me.

I’m pretty sure that if by divine mandate they had to declassify absolutely everything, they would definitely be capable of destroying evidence or reports to make sure we never find out certain “little” (big) details. The point is that something tells me that it is possible that we will never know 100% of the truth and only shades of reality that for us are the big deal but that in the end are not even 10% of everything that is known.