SHARING OF FOLDERS AND FILES INTERNALLY AND EXTERNALLY

I am looking for a freelancer to help me set up a system for sharing folders and files both internally on local pcs and externally. I am looking for someone who is experienced in implementing a hybrid solution that combines cloud-based and local server options. Access control and permissions for users are crucial for my project, and I require strict access control. The ideal candidate will have expertise in implementing access control and permissions for users so that admin can limit users to not be able to delete and not be able to edit etc. Admin user could save a file in a folder which then syncs to all the computers that are linked(that have internet). There must be control that admin can edit or delete but general users cannot edit or delete and only read rights. If admin deletes then it can delete on all computers, however there should be a recovery option in the event that admin deletes in error and needs to recover files/folder also. System should allow admin to be able to add or edit or delete USERS. Each user and admin should have login for the program that resides on each pc. Each user must be able to backup their own folder/files which other users cannot see but admin can see. We have a local server at our office and virtual server. The developer can decide which one is best to host the information. The files/folders must be easily accessible like dropbox ways with file explorer. While I do not have specific requirements for a user-friendly interface for non-technical users, it would be a bonus if the freelancer could implement a very user-friendly interface.