Your leading sentence,
I believe that we humans are forever trapped in our (conditional,
limited, and flawed) perception which separates us from the reality,
Compels me to first expressly distinguish the conception of “knowledge” implied by your “not-knowism” references, from both the notion of “certainty,” and from your
“perceptual separation from reality,”
which in philosophy has come to be known as “the veil of perceptions/ideas,” which posits that:
All we actually perceive is the veil that covers the world, a veil
that consists of our sense data. Since we can only directly perceive
our sense data, all our beliefs about the external world beyond may be
These notions go to the heart of @Conifold’s comment –which pretty much nails the gist of your query.
However, your admitted utter lack of philosophical sophistication, and claimed lack of philosophical interest, partially belied by the fact you actually took the time to pose this particular question, suggests that it may interest you to disambiguate your perplexity by considering the notions underlying the arguably counterintuitive notion of a “veil of perception.”
To do this you will want to examine the [arguably “know-nothing”] philosophy of Immanuel Kant known as Trancendental Idealism, and its distinction between noumena and phenomena: where a noumenon is a posited object or event that exists independently of human sense and/or perception. The term refers to an unknowable thing-in-itself, to be contrasted with, or in relation to, the term phenomenon, which refers to any object of the senses.
The 18th Century philosopher developed the doctrine of Transcendental Idealism in his Critique of Pure Reason, where he argues that:
[t]the conscious subject cognizes the objects of experience not as
they are in themselves, but only the way they appear to us under the
conditions of our sensibility. Thus Kant's doctrine restricts the
scope of our cognition to appearances given to our sensibility and
denies that we can possess cognition of things as they are in
themselves, i.e. things as they are independently of how we experience
them through our cognitive faculties.
In other words, for instance:
In the Critique of Pure Reason Kant argues that space and time are
merely formal features of how we perceive objects, not things in
themselves that exist independently of us, or properties or relations
among them. Objects in space and time are said to be “appearances”,
and he argues that we know nothing of substance about the things in
themselves of which they are appearances.
So here, clearly is a species of the "not-knowism" of which you speak.
It would be interesting know whether you, "an average man who isn't majoring (or even interested) in philosophy!" consider this to be dodging, or a satisfactory answer to, your question. If the answer fails to satisfy the itch, why so?