Display featured products by category. See https://jameshwartlopez.com/plugin/get-featured-products-of-a-category/

display-featured-products-by-category.php

<?php 

// Display featured products by category. on this case its "shirts" which is the slug of the category.
$query_args = array(
    'featured' => true,  
    'category' => array( 'shirts' ),
);
$products = wc_get_products( $query_args );

global $post;
$columns = wc_get_loop_prop( 'columns' );
?>
<div class="woocommerce columns-<?php echo esc_attr( $columns ); ?>">
  <?php
    woocommerce_product_loop_start();
    foreach ($products as $product) {
        $post = get_post($product->get_id());
        setup_postdata($post);
        wc_get_template_part('content', 'product');
    }
    wp_reset_postdata();
    woocommerce_product_loop_end();
  ?>
</div>