Gets primary term name automatically from any post type for The SEO Framework WordPress plugin.

get-primary-term-tsf.php

<?php
// Don't include the PHP opening tag if PHP is already open.

function get_primary_term_name( $post_id ) {

	$taxonomies = array_keys( array_filter(
		tsf()->taxonomy()->get_hierarchical( 'objects', get_post_type( $post_id ) ),
		'is_taxonomy_viewable',
	) );
	$taxonomy   = reset( $taxonomies );

	return $taxonomy
		? ( tsf()->data()->plugin()->post()->get_primary_term( $post_id, $taxonomy )->name ?? '' )
		: '';
}