The development process that my boss called SCRUM. It was anything but. Management thought they could make us do more work than possible.

That sounds familiar :P

That id what scrum is for.
Also, devs are always under delivering and Management is always over asking.

Devs can't prove to managament that they are working their best when they see you out of your desk half of your shift, even if they see a different dev every time.

And management can't prove something can or can't be done on a given time, so they just under estimate.

It's easy, talk it out, build trust, work as a team.
Management is not the problem, the problem is the problem, work together to fix it.