Your unique output is problem discovery related data - find new problems, understand known problems better around your users and key user insights. These are the most challenging ones. It's not something you can show in portfolio, but take through in interview conversations.
Only the solutions side aspects are standard execution, collaboration and data stuff - could be shown in wireframes, prototypes or product demo. They are too basic skills to demonstrate and won't make you stand out. If you put an engineer, designer in room and give them a problem, the will also solve it and make fancy looking outputs. PM's need in ensuring best likelyhood of product success and the 1st point on problem discovery, consumer insights becomes key to ensuring relevancy and succes of the product. That's why good product folks won't ask for portfolio and give take home assignments.
What matters is product success (measures)