"et’s look at what the Scrum Guide says about the role of the Scrum Master"

Well, they keep chainging it. The Scrum Guide has SIGNIFICANTLY redefined the term at least five times in the last ten years.

And a true servant leader has both authority and accountability.

The problem with the role is that it is a non-sensical role. What teams need is a true servant leader. That's not a Scrum Master. Also, a true servant leader would understand the work of the team.