Are some things unknowable?

Starting to think about unknowable, at first, I assured that there is no limits in getting knowledge for people. Although, after a sober reflection I found that there are some areas where we have some basic knowledge that we just assume. I'm not sure we could call it knowledge, cause its more just an assumption. Furthermore, it's almost impossible to clarify some historical obscurities without time traveling due to lack of remaining resources(( I'm not even mentioning future, which is full of unknown. Therefore, I personally believe that there are some unknowable things.

It's a calculator. I have HL chemistry and maths and SL physics in my curriculum, thus I use calculator every day. Every calculator, that you would try to use to divide any number by 0 will display an error. The number, which we should get dividing by 0 isn't defined. It doesn't mean it doesn't exist. We just don't know it. Moreover, we couldn't define it. This is just an example of thing, that we couldn't know due to contradictions to basiс laws of math. Basic laws, that are based on human logic and axioms that we just take on trust, because we couldn't explain them better than just accepting them. Undefining 0 corresponds to logic laws on which we rely on. So dividing by 0 becomes not just an example of smth unknowable, but an example of something that has to be unknowable by a definition, its meaning is to be undefined and this unknowability isn't a gap, it becomes a brick in our building of studying math and understanding the world generally.