Does It Overcome 300k Sync Limit

The Microsoft OneDrive sync tool has a published limitation of 300,000 items that can be synced. If this number of items is exceeded then performance issues may arise.

As per Microsoft's documentation:

If you are uploading, downloading, or moving a large number of files at once, you may need to wait an extended period of time before the sync process can complete. The desktop app taskbar or menubar status icon will show "syncing" or "processing changes" during this period.

Zee Drive is not affected by this limitation of the Microsoft OneDrive sync tool. Zee Drive works with document libraries containing millions of files.