rcp_restrict_activity.php

<?php
/**
 * Require user to have access level to view BuddyPress page
 */
add_filter( 'rcp_member_can_access', function ( $can_access ) {

	$access_level = 4;
	$page_slug    = 'activity';

	$customer = rcp_get_customer_by_user_id( get_current_user_id() );

	if ( empty( $customer ) ) {
		return $can_access;
	}

	global $post;

	if ( $post->post_name == $page_slug && ! $customer->has_access_level( $access_level ) ) {
		$can_access = false;
	}

	return $can_access;
} );