Sharepoint Online. Prevent root-level folder deletion with stopped inheritance

Question

I am using Sharepoint Online and would like to create shared folders structure for our the departments. I created a library named "Departments". For the Departments library people have only "Restricted read" permissions. There I created several folders according to our departments structure. There is what I obtained:

Department library -> HR folder, Marketing folder, Sales folder, .........

After that, I stopped inheritance for each of those folders. It is working perfectly: a user gets access to the library but sees only the folders he has access to. But there is one big issue: regardless of the restricted read permission for the Departments library any user is able to delete a department's folder (HR, for example) if he has "Contribute" access to it. In other words, any teammate from HR dept with "Contribute" permissions could delete the entire folder or move it to another location. Is it possible to prevent users from deleting high-level department folder but have "Contribute" access to all the subfolders? Some kind of "Subfolders and files" option in NTFS permissions. Thank you in advance.

Answer 1

If you have the option to change the approach to one document library per departement then the issue has been resolved as a Contributer can neither add or delete libraries. Otherwise you will have to look into creating a new permission set where the delete option has been removed, but I think it will require a lot of maintanence to make that approach work