Move "writing PBIs" from PO to Team
The Scrum Guide lists as one of the responsibilities of the PO:
"Clearly expressing Product Backlog items"
And then adds:
The Product Owner may do the above work, or have the Development Team do it. However, the Product Owner remains accountable.
In my experience one of the biggest problems with the PO role is that POs tend to become backlog managers, mainly writing User Stories.
Customer contact and prioritization/ordering of PBIs isn't done properly.
In most cases it turned out to be a good idea to involve the team in creating User Stories or even delegate it to the team. Then the PO can focus on his main responsibility of maximizing the value of the product by prioritization/ordering of PBIs.
This thinking could be addressed by moving "expressing PBIs" to the team. With the option that the PO could also be a team member at the same time it would still be possible that the PO person writes User Stories (than as a team member).
That may my suggestion doesn't change the possible division of labour between PO and team but sets another tone.