FreeFileSync Forum

Sure, you just create a separate connection profile for each account, with the appropriate credentials.

+1 for a dark theme/mode.
After 50 years of coding, my eyes really don't cope well with all that white around.

Try mountainduck. It enables you to mount all kinds of cloud storage as a disk in Windows or macOS. I use it all the time with Amazon S3, Google Drive, OneDrive, and Mega.io (via WebDav), and it works a treat. FreeFileSync syncs to/from the mounted disk(s) flawlessly. Mountain Duck isn't free, but ...