What is the correct way to get data in Wordpress from a relationship?

Question

WordPress

Can someone please explain how to get data in wordpress.
For example, there are post types POST_TYPE1 and POST_TYPE2 registered in functions.
Through the ACF, the FIELD1 field is bound to POST_TYPE1, and the FIELD2 field is bound to POST_TYPE2 in the relationship with POST_TYPE1.
I'm doing a taxonomy POST_TYPE2 selection, but how do I get the FIELD1 value from the bound POST_TYPE1 ?

$args = array(
                  'post_type'  =>  'POST_TYPE2',
                  'tax1' => 'tax_val1'
                );
                
                $arrRes = new WP_Query( $args );
                
                while ( $arrRes->have_posts() ) :
                  $arrRes->the_post(); 
...

Answer 1

Can you explain?
Or better yet, with the real names of fields and records, so that the essence of the stored data is clear.