I use pages in WP as a sort-of wiki. It isn't a slipbox, more like a few indexes, but it could be. Biggest hurdle likely is my hesitance in exposing my personal KM notes to the public.

The set-up I use is just WordPress pages, with a plugin to allow categories and tags for pages (separate from the postings cats and tags). This allows having a separate navigational structure for my wiki.
My pages are enabled for webmention.
I (can) use Micropub to publish pages from my Obsidian notes and from my feedreader. It would be interesting in the context of your question to also have an automated way from WP to my Obsidian notes. Perhaps through RSS would be enough.