Into Finder, when clicking on a color tag, loading unfinishing and finally no folders displayed as expected

I had this exact issue recently and these steps solved it for me.

First try to rebuild the spotlight database:

1. Open System Preferences and select Spotlight
2. Select Privacy
3. Drag your HDD icon from the desktop to this pane
4. Wait a second and then remove it.

This should rebuild the spotlight database on that drive.

If that fails you can do it manually using the command line in Terminal.

This command will do a system wide Spotlight reindex:

sudo mdutil -E /

This is a more extensive rebuild as it removes a possibly corrupt index database:

1. mdutil -i off /
2. sudo rm -rf /.Spotlight-V100
3. sudo rm -rf /.Spotlight-V200
4. mdutil -i on /
5. mdutil -E /

There are many websites and forums that explain how to do this.

https://www.macrumors.com/how-to/rebuild-spotlight-search-index-on-mac/