Restrict folders in Files to certain sections/groups/roles?

Canvas does not provide a way of restricting files or folders to Sections, Groups nor Roles.

However, you can make use of Modules* and Assign to to separate content by Section.

This works best if you hide all the other tools (aside from Modules) from the course navigation i.e. your students will not see the other tools on the sidebar and only see what is relevant to them (according to the section they are in) in Modules.

If you co-teach the course, all instructors must agree on (1) using Modules' assign to and (2) hiding tools on the sidebar. This only works if the teachers in the course cooperate.

What about usage rights and user access?

You may have come across usage rights and user access in Canvas' documentation. e.g.

Usage rights and user access refer to copyright information/status of the files/folders in Canvas.

It does not refer to permissions i.e. who in the course can access the file/folder.

There is a workaround which involves using Groups itself, since each group has its own Files. Do note that the workaround has caveats.