If your files have the tag, you don't really need to start playback, just scroll through all tracks. Or use the merge tags to JSON as you did.
If tag is retrieved from bio, preview all tracks for 1 o 2 secs and done.
Note you don't need to preview "all" tracks, just 1 track per artist. Such playlist is created with the "find artist without locale..."
There are multiple scripts using the JSON database, so it's useful to fill it. You have multiple scoring and filter options per country in search by distance with it for ex. Worldmap also comes with a pre-bundled database by default (and if people share their json file, I can add those artists to it).
I may add more code to merge file tags (if present) with the world map JSON for wrapped. But it has zero priority for me.
EDIT: Updated readme, let me know if it's clear enough.
Spoiler (click to show/hide)