Get custom field from a post in rank-math.php

Hi,

I have this function in rank-math.php to change the seo title on some of my posts :

/**
 * Filter to change the page title.
 * 
 * @param string $title
 */
add_filter( 'rank_math/frontend/title', function( $title ) {
	$categories = array_map( function ( $category ) {
		return $category->slug;
	}, get_the_category() );

	if (count($categories) > 0) {
		// Add content to page title for specific post categories
		if ( in_array( 'temoignage', $categories ) ) { 

			$post = get_post();

			// Cannot find function to get a custom field ?
			$job = RankMath\Post::get_meta('job', $post->ID, '');
			
			$text = 'Témoignage %title% '.$job.' %sep% %sitename%';
			
			$title = RankMath\Helper::replace_vars($text , $post );
			
		}
	}
	return $title;
});

I have a custom field “job” in all of these posts, is it possible to access it in the code above ? I cannot seem to find any documentation on all of the available functions for “RankMath\Helper”, “RankMath\Post”, etc.

Thank you very much for your time