As a Scrum Master (using Rapid Board) I would like to restrict users who can add/remove tickets from sprint

As a scrum master, I would like to restrict users who can add/remove a ticket from the sprint. Have a separate permission to enable/disable users who can change the rank of an issue.

Workaround

Restricting the permission Schedule Issues will affect the users' ability to move issues in and out of sprints, as well as ranking them in the board.

When trying to move issues in and out of a sprint or rank them, users without the Schedule Issues permission will see an error message:

Even when accessing an issue the field Sprint will not be editable by users that do not have the Schedule Issues permission. See the recording showing the difference of behaviour between a user that has that permission and one that does not: Sprint field behaviour.mp4

You might want to use the following documentation as reference: Manage project permissions.

That permission affects both ranking and sprint change though. Currently that's not granular. If you are in a scenario where you still need to have users be able to change the order of issues in your board, you might consider changing the order of your board from Rank to something else (e.g. a different field). That way users will still be able to define the order of issues in the board by changing the values on the field used as criteria.