A true Session Manager

// Check if current user is within session limit
if (!apply_filters("is_within_session_limit", true, wp_get_current_user())) {
	echo "You are not within the limit :(";
} else {
	echo "You are good to go :)";
}

// Whitelist user roles
add_filter("is_within_session_limit", "whitelist_roles", 99, 2);
function whitelist_roles(bool $within, WP_User $user) {
    $allowed_roles = array( 'editor', 'administrator', 'author' );
    if (array_intersect( $allowed_roles, $user->roles )) {
        return true;
    }
    return $within;
}

// Set limit for user with ID 8 to 10 sessions
add_filter("session_limit", "increase_limit_user", 99, 2);
function increase_limit_user(bool $within, WP_User $user) {
    if ( $user->ID == 8 ) {
        return 10;
    }
    return $within;
}