Try adding my-query-price to the Class list of the Headline Block in its Advanced setting section. Then add this PHP snippet:
add_filter('generateblocks_dynamic_content_output', function($content, $attributes, $block){
if ( ! empty( $attributes['className'] ) && strpos( $attributes['className'], 'my-query-price' ) !== false ) {
$content = '$'. number_format($content);
}
return $content;
}, 10, 3);
Replace $
with your currency symbol.
Adding PHP: https://docs.generatepress.com/article/adding-php/#code-snippets