I was once responsible for coaching a Product Owner called Jac. It was the product owner for an "enterprise product" - a product sold to big companies to use internally. Sprint to sprint, Jac got to decide what got done. In my book, Product Owner authority went further: what was to be done in future sprints, what kind of things would be done in months to come, and the "roadmap" where the product was going. But... Jac seldom met customers, Jac might talk to them on the phone when they had a problem but Jac didn't talk to the more senior people who signed the purchase orders.
Being an enterprise product, there were consultants in the mix too: installing the product on-site, configure the product, train customers, and hold their hands. They went to customer sites and they met all sorts of people. Naturally, the consultants had a view on what the product should do, what should be developed next, and what should be done in the coming months.