Hmm. The question of how to “archive” notes is a good one.
I would think an archive is counterintuitive in personal knowledge management. Arguably, there shouldn’t be an archive—the system should only contain posts that matter to you in the long term. So I try to keep only notes and ideas that I want to keep.
But I can imagine that after years use things might get messy. Hmm!
The notion of a knowledge hub is similar, in my view, to @nickmilo’s maps of content. In a way the idea of an MoC, index file, or other meta-note also answers the question of an archive. If you maintain those notes actively, they should guide you to the “living” parts of your system. The “archived” parts are the parts not pointed to by those meta notes.
(Further reading: In what ways can we form useful relationships between notes [LONG READ])