IMVHO Johnny Decimal is a good system for paper archives in classic filing cabinets / furniture with many drawers, not much reasonable for computer-based systems.
Beside that IME in PKM/PIM terms we need taxonomies just to manage storage, if it's not managed alone. In that case a time-based taxonomy like an year-based root, a month based II level or so it's enough for storage handling and eventual "time traveling" in noted contents. I have almost anything in org-mode/org-attached binaries, org-mode tangle-d configs and so on, I've tried various taxonomies and in the end just choosing to have subdirs of my org mode root dir one per year just to manage contents. Similarly this is how I split my Beancount-ed personal finance, one note per month.
org-roam-node-find title-based search&narrow access + eventual ripgrep full-text-search are good enough to find anything. Rarely I've used org-ql but it's simply too long to keep consistent notes even with templates to use an SQL-alike querying.
Beside that IME in PKM/PIM terms we need taxonomies just to manage storage, if it's not managed alone. In that case a time-based taxonomy like an year-based root, a month based II level or so it's enough for storage handling and eventual "time traveling" in noted contents. I have almost anything in org-mode/org-attached binaries, org-mode tangle-d configs and so on, I've tried various taxonomies and in the end just choosing to have subdirs of my org mode root dir one per year just to manage contents. Similarly this is how I split my Beancount-ed personal finance, one note per month.
org-roam-node-find title-based search&narrow access + eventual ripgrep full-text-search are good enough to find anything. Rarely I've used org-ql but it's simply too long to keep consistent notes even with templates to use an SQL-alike querying.