Different options per post type in WP_Query

Question

I have two post types (type-A and type-B) and two taxonomies (tax-1 and tax-2), both assigned to each post type. This means that posts from type-A can contain terms from tax-1 and tax-2 and posts from type-B can also contain terms from tax-1 and tax-2.

I want my WP_Query to output all posts from type-A that contain certain terms of tax-1. But I don't want to output type-B posts that contain these tax-1 terms, which my WP_Query unfortunately does. The same should apply to tax-2, whereby only posts from type-B that contain terms from tax-2 should be output.

I have already tried to create two $args for this, but I did not manage to merge the two $args.

function my_function($args) {
    global $post;

    $args = array(
            'post_type' => array('type-A','type-B'),
            'tax_query' => array(
                'relation'  => 'OR',
                 array(
                    'taxonomy' => 'tax-1',
                    'field'    => 'term_id',
                    'terms'    => array(11, 12, 13),
                ),
                array(
                    'taxonomy' => 'tax-2',
                    'field'    => 'term_id',
                    'terms'    => array(21, 22, 23),
                ),
            ),
        );

    return $args;
} 

Answer 1

You could use pre_get_posts to conditionally add the tax_query depending on post-type, here's a simple example.

<?php
function wpse_377928( $the_query ){
  $post_type = $the_query->get('post_type');
  if ( 'type_a' === $post_type ) {
    $tax_query = [
        [
            'taxonomy' => 'tax-1',
            'field'    => 'term_id',
            'terms'    => array(11, 12, 13),
        ]   
    ];
  } 
  elseif ( 'type_b' === $post_type ) {
      $tax_query = [
        [
            'taxonomy' => 'tax-2',
            'field'    => 'term_id',
            'terms'    => array(21, 22, 23),
        ]   
    ];
  }

  if ( !empty( $tax_query ) ) {
      $the_query->set( 'tax_query', $tax_query );
  }

}
add_action('pre_get_posts', 'wpse_377928');