That is what Schopenhauer says yes. Willing is much more direct according to S. When we experience pain for instance we experience pain, pure and simple. It does not matter whether the pain is caused by a phantom limb or by a small black box like in the book Dune. The pain is real. So Schopenhauer state we have access to the real via another way than our reason, namely our will. Clever man Schopenhauer was, very clever. Clever and cranky though, very cranky.

yes, but with respect to premise 2- We know that we act directly/unconditionally- in order to for his argument to be formally valid, should he not have this premises states as: "we know we act ONLY in a direct/unconditioned way"?

I'm sorry, jancanc, but I am not sure what question you are asking here? Everything in your post is correct, I think. What exactly are you asking?

It is valid!

If anything is an appearance it is known conditionally
We know that we act directly/unconditionally
Therefore action as such cannot be a appearance. — jancanc

Actually yes, I think it is.

Is this a duplicate discussion?

https://thephilosophyforum.com/discussion/12398/what-do-we-call-a-premise-which-omits-certain-information