I'm happy to hear this plugin meets your expectations!
Thank you for the suggestion!

In that case, how about these settings?

Sync Type: Articles, highlights and annotations
Article Labels: Specify the unique label, such as "joplinsync," so only articles with the label are synced as the entire article.
Highlight Labels: Leave empty to sync every highlight and annotation.

With this configuration, sync articles if they have the specific label, and leave every article not synced
while all the highlights/annotations are always synced.