Its not a trivial puzzle, cause:
https://meta.discourse.org/tag/chat/l/latest
Has:
So are you in a transition point between “Tag centric” routing at that point to “category centric routing”
Long term I do wonder if we totally let go of “tag centric” routing and just rely on ?tags=... for all tag filtering of topic lists, cause now the routing rules are just way to elaborate for my liking.