An expert is a person that understands enough of the law BUT ALSO know how and what to do to be on the road to compliance.
An expert is not a lawyer that has analysed the law to bits and pieces.
An expert needs to understand your organisation, corporate strategies and priorities and must ensure they state the importance regarding compliance with GDPR.
An expert needs to be capable discussing with developers (if you have them) about whats right and whats
An expert is the one who knows what to do to be compliant.
Legal advice regarding the laws is important for review and/or input.
But you have to have competence, skills and experience regarding information: