One issue I see in this discussion is "What do you* mean by 'know'?"
* btw "You" in the general sense, not you specifically.
The problem is that of coming to grips with whether it is ever possible to "know" anything
There are various senses of that word "know" so I would be curious to know (LOL) what word Plato used specifically. For example:
I know I'm alive
I know where I am
I know 2+2=4
I know the capital of the US is Washington DC
I know the universe was in a hot dense state at one point
And so on