Ask HN: Concept Taxonomy Tools?

I've got a Pocket bookmark repo with ~15K articles in it. I'm reasonably disciplined about tagging each saved article, but am swimming in tags (~1200). I'm attempting to organize the tags offline using pencil & paper (doing it in a code editor isn't cutting it.). Pocket attempts to streamline things but their UI leaves a lot to be desired - and is platform dependent.

It's a laborious but interesting exercise - the paper taxonomy looks like it will have 50-100 top-level topics with 10-30 subtopics under each.

- Some are concatenations (jobdefs-career-work, fun-humor). - Some have multiple meanings (attention/behavior & attention/LLMs). - Some are being renamed as I go. (chat -> chatgpt)

Once complete I'll try matching this list with another pulled from my personal Jekyll site.

I looked at 1-2 online taxonomy tools before embarking on this sacred quest. Does this community have a favorite tool, for this type of job-to-be-done?