We usually disable the privilege that allows the student role to view the "Participants" section.

How? Well, it depends on the scope of the restriction. Therefore, it can be done at two levels:

At the course level

We would remove the privilege for users whom we do not want to see that list.

Click on Course administration > Users > Permissions and filter the privileges by typing viewparticipants (view participants)

For the 'View participants' capability, remove the student role by clicking the trash can next to the role name and confirm.

At the instance level

This must be done by an administrator and would affect a certain role in all courses.

Go to Site administration > Users > Permissions > Define roles and edit the role you want to restrict, removing the privilege viewparticipants from it.