How do topics emerge in a bottom up ZK?

Hi. I have a few failed ZK attempts behind me in which I focus too much on the top down approach, obsessing on which hub notes (or MOCs, indexes or "structure notes") a new note should be linked from and also focusing on colleting notes rather whan thinking about notes, leaving me overwhelmed and demotivated. So its clear I need a different approach. I really like Sönke Ahrens's approach in "How to take smart notes", and would like to give this a try. With this in mind I could need some advice on how to let topics emerge from the notes themselves. Ahrens is (likely deliberately) a bit vague on this, but from my understanding he regularly scans his existing notes and look for new topics. This sounds good enough, but how exactly would one do this; would you add every single note to an (alfabetical ordered) list, and simply read through it from time to time and see what pops out? He also mentions (maybe in the book, but also in YT-videos) using keywords (i.e. tags) to make up an index, but I'm not sure how that process would go as far as developing new topics; does he tag each note with something that resembeles a topic (broad such as "psychology" or maybe a bit narrower such as "systematicErrorsInThinking")? What about using forward links (i.e. links to non-existent notes) instead of tags? I know there are not hard rules and that I should find what works for me, but having failed multiple times av ZK I'd really appreciate advice on this particular issue to increase the odds of my next attempt being successful.
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How do topics emerge in a bottom up ZK?

How do topics emerge in a bottom up ZK?

How do topics emerge in a bottom up ZK?