Force logout when role is changed

The wp_login hook you are using only triggers when a user login, while we need to trigger function when user changed their role.

The correct for this will be set_user_role hook.

Please update your code with the given code so User will logout on changing the role.

function logout_pending_users( $user_id, $new_role, $old_roles ) {
    // Here we are getting the user object.
    $user = get_userdata( $user_id );

    // If the user no longer has the 'read' capability or if the new role is 'No role for this site'
    if ( ! $user->has_cap( 'read' ) || $new_role === '' ) {
        // Here we are logging the user out.
        wp_logout();

        // Here we are destroying the current session and clear cookies.
        wp_destroy_current_session();
        wp_clear_auth_cookie();
        wp_set_current_user( 0 );

        // Here we are redirecting the user to the homepage or any other URL as per our need.
        $redirect_url = esc_url( home_url() );
        wp_safe_redirect( $redirect_url );
        exit;
    }
}
add_action( 'set_user_role', 'logout_pending_users', 10, 3 );