The relationship status of Product Roadmaps and Product Managers: it's complicated. To get some great words of advice you better listen to this episode with Janna Bastow. She shares her wisdom and practicable tips how to deal with product roadmaps.
If you want to reach out to Janna, you can find her on Twitter and LinkedIn.
Two more additions:
(1) We talked about the "Agency Trap" - you can read more about this here.
(2) ProdPad has a public roadmap, check it out here.