First, thanks for a hugely informative essay.

Isn't the real question the possibility of knowledge that other people can be required--or at least expected--to accept as knowledge? I would say that my belief in God is a form of knowledge: I know that God exists (and I do mean that). Yet, I understand that such knowledge is matter of faith: without evidence (within material existence). So I cannot expect, much less require, anyone to accept it as knowledge (though someone might 'take my word for it').

Much of the knowledge of material existence that exists today requires special training/equipment that is simply not available to most people. It is a matter of 'taking someone's word for it'. For whatever reason, that has become anathema for many people. Many people insist that there is no difference between that and accepting, say, someone else's professed belief in God.

Even so, there are experiences of material existence that all people can verify for themselves. Knowledge following from such experiences establishes that knowledge that people can at least be expected to accept can exist.