Restricting roles a user can switch to

This is a tricky thing to achieve because there’s an assumption that a user needs to be able to edit a user in order to be able to switch to that user, and typically only Administrators can edit users.

You should be able to achieve this with some custom coding if you’re familiar with the roles and capabilities system in WordPress or can find someone who is. This add-on plugin is a good place to start as it filters the ability of a user to switch to another account based on the target user: https://github.com/johnbillion/user-switching-for-regular-admins/blob/master/usfra.php

Sorry I can’t help any further but I’m very busy currently. Best of luck!

I was able to accomplish this by hiding specific roles from other roles using code from here:

https://stackoverflow.com/questions/51667858/hide-specific-users-role-from-users-list-wordpress-admin-dashboard