The worst project managers I've worked with have been keen on deadlines without understanding what they're asking for. They're more interested in schedules than understanding the details of the project.
The best project managers are ones that either know the domain inside out or are good at getting the best out of people (and that doesn't mean acting like a slave driver). I've never met one that had both, but I can imagine they aren't short of money.
They want the project to progress. Desperately.
From their point of view they're often powerless people surrounded by line workers that don't want to interact with them, yet they're somehow responsible for the success of the project. They're acutely aware that the meetings are often pointless for workers, deep inside, they know that coloring red/yellow/green rectangles on a gantt chart is of little value.
You can use that to your advantage if you make a request and frame it such that they can advance your progress concretely by helping you in some way that isn't possible for you to do alone.
I've repeatedly hammered home that we're understaffed. Those with the money to spend on staff seemingly couldn't care less. Any middle managers are stuck between a rock and a hard place. The phrase 'rearranging deck chairs on the Titanic' springs to mind.