With John Locke things have primary qualities and secondary qualities. Primary means in themselves. Secondary is things that they have only because of our sensing them. [Like it feels hard and cold.] Kant noticed all qualities are secondary. Everything you know about a thing are things you know in relation to yourself. So what is left? The thing in itself. That is like the old difference between form and content. The thing is the content and the form is your categories that you put it into. [The categories are like computer chips that process the information.] But "It exists" or "It does not exist" are also a priori forms . So we add that also? Then the thing in itself maybe is just not there?
With Fries immediate non intuitive knowledge is how content is known. So this sort of knowledge does answer that question and many more.
With Hegel, the Logos [in Neo Platonic philosophy] is the source of everything. Not just the logical forms, but even beings. So our minds (which are small parts of the Logos) perceive immediately the categories.
And with Hegel just pure reason can know things. [So that is very close to Fries -- as far as I can see,-we know the thing in itself by reason to Hegel, and by a sort of knowledge that is not reason to Fries.]
So what I getting at? It is that I think both Fries and Hegel are important. [But I should add that both are in some need for sieving. There are along the way lots of places that can cause misunderstanding. And when I say Fries I really mean how that approach was developed by Leonard Nelson and Kelley Ross. When I say Hegel while I think it is fairly plain and simple, but I can see that McTaggart and Cunningham added clarity where before there had been misunderstanding.
In any case, I see "Back to Kant" straight just means the old problems cropping up again as was noticed immediately after the Critique was published
