A few years ago I quantified the 4 Quadrants of the Product Owner role as a means of communicating the depth and breadth of the role.
My intention at the time was to provide guidance to agile teams about the level of difficulty in performing within the role. I also had the intent to provide enough nuance so that Product Owners would realize that they typically would need help. That even though Scrum emphasizes a singular Product Owner per team (backlog), that more than one person might be needed to help fill all of the requisite skills and daily chores.
As part of the 4 Quadrants, I bundled the activities of a Business Analyst under the Product Owner role. It doesn’t mean that the Product Owner needs to be a Business Analyst. It just means that they have to either (1) have these skills themselves, or (2) have access to these skills within their team in order to effectively perform their job.