Hi @Danny Jean-Baptiste,
To sync SharePoint files to OneDrive in online-only mode, you can enable Files On-Demand for your users. With this feature, you’ll see all your files as online-only files in File Explorer, but they won't be downloaded. When you’re connected to the Internet, you’ll be able to use the files like every other file on your device.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.