Filter? The search bar is powerful: And, Or and Not can be used to build a search.
You can save searches.
You can use them to create a VL (Virtual Library).
All without the overhead of composite/calculated column has.
I also CLEAN and re-tag as there are quite a few Authors (Agents) That over load the Tags. (5 ways to represent Science Fiction
14 ways for Magic
)
I make them hierarchical . Base is the main topic. Then the category.
Science Fiction.Military (AKA Mil SF). Fantasy.Epic, Fantasy.Urban Do you really search for a specific type Fantasy creature??
I might include key characters as a tag, but not every one in the book.
Places if important (historically). If the story holds together in Anytown USA, why list the town?
IMHO 5 tags max for 95% of your library
And a simple 2nd search on spin-off series might cover the new main players in the overlaps .
BTW I do Series hierarchical also.
In many cases the spin-off is the second part. But I do have ONE custom Series column for when the spin-off gets its own life
Lean - mean will always have better performance