Right now mine looks like this:
Pages:
Topics:
I wonder if there’s a better way to organize my digital archive. I’m thinking I could embed pages, but this might not be a great long-term solution as I’m bound to add more and more notes to Obsidian.
Looking forward to hearing your thoughts! 
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])
Yes, I came across the idea of an index file. I’m considering this approach. I’m not sure if there’s a better strategy to be honest. This is probably what I meant by a ‘digital archive’.
It seems like our philosophies differ to an extent. Ultimately I want my personal knowledge base to contain content I consumed in the past, content I’m processing right now, and things I’m putting away until a later point in time.
But I do agree, after a while my ‘collection’ is bound to become overwhelming. Do you simply discard notes once you don’t find them useful any longer? How do you determine that a note or idea is no longer of use or interest to you?
You’re asking the hard questions!
At the moment, I have an archive database in DEVONthink where I put e.g., everything related to past jobs I’ve held, completed courses, and the like. But that was pre-PKM for me. There are definitely notes in there that are lost to the ages, for now.
Moving forward I aim not to do this, because I’ve had occasional failed searches for notes or ideas in which I forgot to search the archive. Still, the solution isn’t just “add the archive back into my main system”, because it is massive and would make most searches quite noisy.
So I’m in transition!
Aah I see! Agreed, discoverability is an issue in the long term. I’m right at the start of my PKM journey so I have many things to figure out, this included. 
I can understand wanting to archive content that you don’t plan to look at again. I have something of an “archive” with articles I download to markdown.
My thought process is that I take these articles and made notes from them. I won’t reference the article itself normally, but I’d still like to have the original for whatever reason.
This is just a folder called “Articles”- So I’ll download an article to markdown, save it to my main directory, link to the notes that I make, and then put the article into the Articles folder.
I’m not sure if I’d archive my notes though, it’s hard to imagine looking at something and thinking “I will never look at this ever again.” But I also haven’t had an issue where the amount of notes I have gets in the way of searching for something.
I suppose it’s wrong of me to call this an ‘archive’. Perhaps it’s better to see it as some sort of a knowledge hub or knowledge base. I think that’s closer to how I intend to use it. This is simply a collection of notes and other content that I’ve consumed and processed that now reside in one central location. Having everything in one place should ultimately help me search, discover and find content when I need it. This is where having an index might come in handy. In fact, I think this might be the solution to my problem.