Sharepoint file locking alternative

Good evening!

I manage a fleet of laptops using Microsoft Intune.
Our Microsoft 365 Business Premium subscriptions include Sharepoint Online and I'd like to use it as a file server.
Everything works fine except for one specific point: locking files during editing.
With a Windows Server file share, when someone wants to access a file being edited, a pop-up appears, inviting the user to open it in read-only mode, notify the editor, etc., which avoids the risk of conflict.

With Sharepoint, it's more complicated.

Here's the scenario:

• Sharepoint files are synchronized on PCs via OneDrive with the Intune configuration “Configure team site libraries to sync automatically, Use OneDrive Files on-demand and Convert synced team site files to online-only files” enabled.
• User 1 double-clicks on one of the files in the OneDrive folder, and a local copy is downloaded.
• User 1 edits the file via Word installed locally, while the Internet connection is lost.
• At the same time, user 2 edits the file and saves it. His version ends up on Sharepoint.
• A few minutes later, once User 1's connection is re-established, his version is saved on Sharepoint.
  User 2's changes will go completely unnoticed, creating confusion and wasted time.

The check-out/check-in system proposed by Sharepoint has the merit of existing, but is very restrictive for users.

Is there a way of ensuring that Sharepoint files appear in the OneDrive folder in Windows File Explorer, but that modifications can only be made online, to avoid this type of problem?

I thought that the “Convert synced team site files to online-only files” option would meet this need, but it seems that this is not the case.

Thanks for your help!
Jo