If your post is a fictional story or it's about writing fiction, tagging it fiction is appropriate. But don't tag fiction on a post about football or laptop batteries. I've seen both. I'm not sure the last two gain you anything. Consider a genre related tag instead.
The system allows five tags. I've been told always fiction first when I post fiction. Others can be edited in seven day window, but never the first one.
it sound as if it's on the K.I.S.S. methodology. So something like Fiction fantasy Wiess-tales and Journey-saga should be enough. Fiction because it's fiction, Fantasy as a sub-genre, Wiess-tales as a catch-all for my works, and Journey-saga for the overall series.
That makes sense. Thank you, @bex-dk
Only tag searches only seem to work for 7 days. But test it. Check one of those tags and see if you can find the old stuff with it. I recall someone having done that and being unable to. I would probably do fiction story fantasy... possibly writing.