'PM' - well, there's a problem. We don't have project managers. Product -owners-, yes.
But you have a point; a lot of places try to 'be agile', as something the devs do, without also including management. As a number of others in this thread even indicate. Management has to also change, or else there's a mismatch in expectations.
As a dev doing SCRUM, we report point totals, and allow the business unit to prioritize stories based on that, and based on the need for the feature. Point totals above 8 or so we try and break down into more stories. The only guarantee we give is that if we include it in a sprint, we will get it done in that sprint. We can estimate it at ~8 hours (~two days of a single dev's time; we build in slack, for meetings, context changes, dev tasks, and the unexpected), but we aren't guaranteeing that you'll have it in two days; it'll be the end of the sprint. Any more exact estimate is only for other devs, in case they're reliant on it being in place for something they're working on.
But you have a point; a lot of places try to 'be agile', as something the devs do, without also including management. As a number of others in this thread even indicate. Management has to also change, or else there's a mismatch in expectations.
As a dev doing SCRUM, we report point totals, and allow the business unit to prioritize stories based on that, and based on the need for the feature. Point totals above 8 or so we try and break down into more stories. The only guarantee we give is that if we include it in a sprint, we will get it done in that sprint. We can estimate it at ~8 hours (~two days of a single dev's time; we build in slack, for meetings, context changes, dev tasks, and the unexpected), but we aren't guaranteeing that you'll have it in two days; it'll be the end of the sprint. Any more exact estimate is only for other devs, in case they're reliant on it being in place for something they're working on.