Synergy has an option to recreate your document folders on your on-premises file server.

When you create a new project, it creates a folder in Project menu > Documents > Document library in the cloud. The folders are then automatically created on your on-premises file server.

All new project folders will be synced to your server local drive.

What doesn’t it do?

It doesn't:

Delete local folders
Rename local folders
Sync old project folders, except a new child folder be created
Do anything with Staff or Contacts folders