The data controller (DC) has the obligation to ensure the compliance of its personal data processing.
If the DC has appointed a data protection officer, it asks for advice and instructs it to ensure the execution of the DPIA.
If a subcontractor is involved in the processing, it must provide its assistance and the information necessary for the completion of the DPIA.
Finally, the data controller should also seek the opinion of the persons concerned by the risky processing or, otherwise, justify this non-solicitation.
For your dpia to be complete, the professions (project management) and the persons in charge of information systems security must participate in the process of producing the DPIA and its validation.