Access control in NextCloud + webdav how?

Question

webdav

How to organize folder access control in NextCloud? There are 30 users, they have personal accounts, user groups are also created according to departments. The task is to create the following folder structure "Department folder" in it "Personal folders of department employees" (where the employee and the administrator of the NC have access) and "Public folders of the department" (where the employees of the department and the administrator of the NC have access) and "The general folder of the department FOR ALL employees" (where all employees have access)
And most importantly, how to save the structure and access rights when connecting via webdav? because when connected, the employee sees a mess of folders without a structure.