Project managers basically do something that the devs, especially dev manager, can handle themselves. It seems like a leftover process for when software contracting was more common. There’s no reason a developer can’t just manage the Kanban board and write a quick report.
Product managers can be really good but in a lot of cases they just devolve into stakeholder management with poor/no vision. Because they talk to upper management a lot they can get a lot of credit for things they didn’t have a lot to do with, because they’re the visible face for it. This can sometimes lead to the Product org getting too big because they get promoted up to Director and now need 10-100 reports for something that only needs like 3 Product managers max. Then you’re in a really bad spot because you’re going to be bothered by PMs with small scope a lot about stupid shit