Hi
Thank you for posting the thread on our forum.
Based on your description, we did a test on our end. We create a folder in sharepoint site and sync it to OneDrive.
Then open the file explorer>delete the folder >then we find the folder will be deleted from file explorer, sharepoint site and onedrive.
Files deleted from the shared library are no longer available to anyone and can be restored from the shared library's recycle bin within the next 93 days.
Then you can just go to onedrive recycle bin to recover the folder
Hope the information can help you, if if there have any misunderstanding, please feel free to post back.
Best regards,
Stacey