There are two types of scrum masters. Those who are true believers in agility, and those who think it's just a fancy bullshit name for "project manager". The latter tend to be the the fucking worst, unfortunately they're the most common breed.

Truth is, a real "scrum master" (or "agile coach" for SAFe 6 people) is at best a part time job, and has only two purposes. With experience and knowledge, help the team towards making their job easier/faster/more interesting/more predictable/more serene through continuous improvement using agile methods as a toolbox (and NOT a fucking dogma), and ~~tell idiotic managers who can't fucking anticipate a fucking deadline more than 3 days in advance to fuck off and stop being fucking morons~~ teach managers to respect agile principles and have a clear short- and medium-term vision so their needs can comfortably fit the team's backlog without jeopardizing the team, other priorities or the deadlines.

The other breed are fucking corporate yes-men who shove work over capacity onto the team and play make-believe-scrum by focusing exclusively on bullshit rituals that serve no actual fucking purpose.