For a product marketing designer, portfolio proof is mainly an ownership decision. The page should make clear what this role approves, what it only prepares, and who receives the asset next.
For product marketing designer, keep the portfolio proof pass focused on problem statement, constraints and decisions, and before-and-after evidence. Make one controlled change at a time and retain enough evidence for another person to repeat the decision.
Show the problem, constraints, decisions, before-and-after evidence, and final result without exposing confidential source material. Apply this portfolio proof guidance to the actual product marketing designer delivery path.