How to stop a Line Manager and HR from creating Document of Record for themselves

Summary:

Dear Team,

Our business requirement is to stop Line Manager and HR from creating specific Document of Record for themselves.

For example, there is a document for Secondary assignment which Line Manager can create for their direct report, but the Line Manager should not be able to create the same Secondary assignment DOR for themself.

Please suggest a way to enforce this.

I have already used Document Type level restriction but that completely stops the Line Manager from creating the document. (this is not the requirement)

I have also used document security policy. As line manager is allowed to create for employee, and user has both employee and line manager role, the line manager is also able to create for themself.