If you are asking related to Agile world (mainly Scrum) my recomendation is going directly to the Scrum Guide. No other source of information is valid. You can find the Scrum Guide for free here https://www.scrumguides.org/. Related the project manager role definition you can take the PMI definition or any other organization but it will not differ to much. Saving Changes...
Where I work, project manager is the one leading the project team under the guide of a project lead, and project owner is the business entity/person who will follow up project in the interest of its business (eg. Operations, Maintenance, HESQ, etc). Both PM and Product Owner must work hand in hand to achieve the project's objectives, just roles differ.
Reference in PMBOK 6th edition:
4.2.3 PROJECT MANAGERS USE SERVANT LEADERSHIP
The PMBOK® Guide – Sixth Edition, defines the project manager as “the person assigned by the performing organization to lead the team that is responsible for achieving the project objectives.”
Many project managers are accustomed to being at the center of coordination for the project, tracking and representing the team’s status to the rest of the organization. This approach was fine when projects were decomposed into siloed functions.
However, in high-change projects, there is more complexity than one person can manage. Instead, cross-functional teams coordinate their own work and collaborate with the business representative (the product owner).
When working on an agile project, project managers shift from being the center to serving the team and the management. In an agile environment, project managers are servant leaders, changing their emphasis to coaching people who want help, fostering greater collaboration on the team, and aligning stakeholder needs. As a servant leader,
project managers encourage the distribution of responsibility to the team: to those people who have the knowledge to get work done. Saving Changes...