Add this code snippet in Child theme function.
function wplms_custom_search_filter($query) {
if ( !$query->is_admin && $query->is_search && $query->is_main_query() && !isset($_GET['post_type'])) {
$query->set( 'meta_query', array(
'relation' => 'OR',
array(
'key' => '_wp_page_template',
'value' => 'start.php', // page template file name
'compare' => '!=',
),
array(
'key' => '_wp_page_template',
'value' => 'create_content.php', //page template file name
'compare' => '!=',
),
));
}
return $query;
}
add_filter( 'pre_get_posts', 'wplms_custom_search_filter' );