The Database contains no tags for images with the Apple heic format. I double checked that there are some images which do contain tags but they do not land in the database.
Appearantly, digikam does not write Tags to HEIC files but keeps them in the database only (as per https://exiftool.org/forum/index.php?topic=12876.0). That would explain something, I will investigate further...
The Database contains no tags for images with the Apple heic format. I double checked that there are some images which do contain tags but they do not land in the database.