Is it possible to set a role specific value for "allow_insecure_uploads?" I want to override the value for "allow_insecure_uploads" which is in system.file config, but only for specific roles. Am I going to need to do this in a module / does one already exist?
Module suggestions are usually frowned upon on DA, but regardless the answer is yes; role-specific config values are possible via the D8 config override system.

The Drupal 8 docs has a section on the config override system with a relevant example in the Providing overrides from modules section. After you've declared the override class in your module's .services.yml &amp; created the override PHP class, you'll do something like this in the loadOverrides() method:

 public function loadOverrides($names) {
    $overrides = array();
    // @TODO: define a hasRole($role) class method that checks Drupal::currentUser() for a given role
    $has_role = $this-&gt;hasRole('my_role');
    if (in_array('system.file', $names) &amp;&amp; $has_role) {
      $overrides['system.file'] = ['allow_insecure_uploads' =&gt; TRUE];
    }
    return $overrides;
 }