So much philosophy is playing with words.
Eastern philosophy has nailed this thousands of years ago and we westerners are up to this day totally in the dark. We actively treat the I as a concrete object that really exists as an entity. It does not hold any closer examination and evaporates entirely the closer it is questioned.
That's just part of how our language works. It doesn't seem to matter whether I am a "concrete object" or some swirly pattern of becoming or indeed even an illusion! The English word "I" does not refer to an eternal soul or "atman."
If you stare long enough at an ice cream you'll have the marvelous insight that in reality there is no concrete ice cream entity, not least because it melts. Yet people don't go around saying "wake up, there are no ice creams!" Why is that?
And while everyone loves to run in circles around the argument “but how can you know with certainty” the fact is that I am as certain that this assumption holds as I am that it provides no value at all to continually question if reality is really real, you’d have to take that as an assumption to ever have any kind of value adding discussion.
The people who insist we can’t know if anything is definately true must agree that they can’t know if that assertion is definitely true, so they sort of kill their own argument axiomatically.
Why deny the word has meaning, just because you can't distill it down to a concise explanation? The meaning of a word can be arbitrarily complex. Knowledge can exist, even if you can't define it, because meaning is not determined by definition. Definitions are simply a mechanism for coordinating understanding, not for demonstrating its existence.
Besides, any argument against the existence of knowledge could be used against belief. Play "taboo" with the subject and don't confine yourself to using ancient terminology to describe the world and these pointless linguistic problems melt away.
Anyway your definition is wanting. A religious scientist has two kinds of clearly different beliefs: faith and knowledge. A mathematician has the same two kinds, under different names: axioms and deductions.
Saying that axioms are the same as deductions is a radical claim.
You can apply that to the real world if you then add social processes and see "knowledge" or "truth" as shared belief between a chosen set of people (or all of humanity). Then you can go down the whole rabbit hole of beliefe aggregation and voting theory.