Rogier H. Riana J. Got this reply from email support:
Yes - all sub-folders within the knowledge base will be synced!
The Knowledge Base automatically refreshes every 24 hours to ensure your content stays up-to-date. However, if you need to push immediate updates—for example, when you've added new product documentation or updated pricing—you can trigger a refresh using two available actions (including removing files):
Resync Knowledge Base
Resync Knowledge Base Entry
The Resync Knowledge Base action updates your entire knowledge base, while the Resync Knowledge Base Entry action lets you refresh specific entries. Add these actions to your Lindy whenever you need real-time updates between automatic syncs.
However, as you can see in my other thread, the syncing is not actually working as expected for a large (100+) collection of Google Drive files.