Always enable Downloadable option

add_action( 'wp_footer', function() {

	?>

	<script type="text/javascript">

	document.addEventListener('DOMContentLoaded', function() {

		var downloadableCheckbox = document.querySelector('input#_downloadable');

		if (downloadableCheckbox && !downloadableCheckbox.checked) {

			downloadableCheckbox.checked = true;

			// Trigger WooCommerce's change event so it updates related UI

			downloadableCheckbox.dispatchEvent(new Event('change', { bubbles: true }));

		}

	});

	</script>

	<?php

});