Filter ACF post_object by taxonomy when on taxonomy page

functions.php

<?php

 class acf_filter_post_object {
 
  static function setup() {
    add_filter( 'acf/fields/post_object/query/name=FIELD_NAME', __CLASS__ . '::only_current_terms', 10, 3 );
  }

  /*
  Only current terms to be shown within the taxonomy
  page for the post_object type of selection
   */
  static function only_current_terms( $args, $field, $post_id ) {
    // Due to the AJAX request, there's not a way
    // to get the query to work without doing some
    // dangeous sniffing
    $url = parse_url( @$_SERVER['HTTP_REFERER'] );
    if ( ! $url || ! isset( $url['query'] ) ) {
      return $args;
    }

    // Get the query, split it into an array
    parse_str( $url['query'], $query );
    if ( empty( $query ) ) {
      return $args;
    }
    // Check that it contains the right taxonomy
    if ( 'product_cat' !== @$query['taxonomy'] ) {
      return $args;
    }

    // Check if theres an ID involved
    $term_id = (int) @$query['tag_ID'];
    if ( ! $term_id ) {
      return $args;
    }

    // Add a tax query to filter out all products
    // that aren't in this specific category
    $args['tax_query'] = [[
      'taxonomy' => 'product_cat',
      'fields'   => 'id',
      'terms'    => $term_id,
    ]];

    return $args;
  }
}

__CLASS__::setup();