How a feature UX should work based on the PM having a fair bit of expertise in the field? Maybe.
What task you work on next? Maybe not.
You see the problem with letting someone who's not an expert in the work decided the work goes both ways. The PM is in charge? Good luck getting patching on the backlog. Don't consult the PM? Good luck getting the functionality right.
My takeaway is the PMs often aren't the experts in writing, maintaining, or running a production system, thus they probably shouldn't actually run the backlog. But said production system is pretty useless without market fit, so you want to strongly align with whoever your version of a PM is.