WordPress stores the page id for the privacy policy page in the options
table. To get the value, you can use:
$privacy_policy_page = get_option( 'wp_page_for_privacy_policy' );
if( $privacy_policy_page ) {
$permalink = esc_url( get_permalink( $privacy_policy_page ) );
}
The $privacy_policy_page
variable holds the ID of the privacy policy page.