Assuming that you’ll be trying to get this outside of the loop. The first thing you need to do is get the post ID, you can do this the same way that you’re getting the term in your code
$queried_object = get_queried_object();
$post_id = $queried_object->ID;
Then you need to get the post categories https://developer.wordpress.org/reference/functions/wp_get_post_categories/ and loop through the categories and get the term ID and then get the field from one of them the same way you’re getting it above.
