I can resonate with most of what you've written as a developer who has recently become a manager. But, I would not delegate to the manager to shield the team entirely.

I strongly believe in empowering everyone in the team to give input not only for the roadmap but also on what to work on first. I make sure all obstacles are removed and if there is a need for more time, then be it. After all, in agile, everything changes all the time.

It's all about communicating things properly and prioritising the deliverables that bring the most value.