hi @craigrlong,
odrive will provide full bi-directional sync. We can also provide encryption features.
This is a good place to start for learning what odrive can do and how it might fit your use cases:
Here are our specific pages explaining sync: Download universal cloud sync - Get all your files in one place and encryption: Zero-knowledge encryption for Dropbox, Google Drive, OneDrive, Box, S3, WebDAV, FTP, and more