Simple plugin that sets Digital License Manager defaults when you publish a new products. To install this, drop it in mu-plugins or plugins dir.

dlm-product-defaults.php

<?php

/**
 * Plugin Name: DLM Product Defaults
 * Description: Sample plugin that sets product defaults when you publish a product for a first time or create via Woo APIs. 
 * Author: Darko Gjorgjijoski
 * Version: 1.0.0
 * License: GPLv2 or later
 */
 
if ( ! defined( 'ABSPATH' ) ) {
	return;
}

class DLM_Plugin_Product_Defaults {

	/**
	 * Constructor
	 */
	public function __construct() {
		add_action( 'woocommerce_new_product', [ $this, 'new_product_set_defaults' ], 10, 2 );
		add_action( 'transition_post_status', [ $this, 'new_product_published_from_admin' ], 10, 3 );
	}


	/**
	 * Returns default product values
	 * @return array
	 */
	function get_product_defaults() {
		return [
			'dlm_licensed_product'                      => 1, // or 0 for no.
			'dlm_licensed_product_delivered_quantity'   => 1, // how much keys to be delivered upon purchase.
			'dlm_licensed_product_licenses_source'      => 'generators', // or 'stock', if 'stock', then the bellow generator id is not required.
			'dlm_licensed_product_assigned_generator'   => 1, // generator id, found in License Manager > Generators
			'dlm_licensed_product_activations_behavior' => 'standard', // or 'quantity'
		];
	}

	/**
	 * Set's initial Digital License Manager settings when using the WooCommerce's PHP API
	 *
	 * @param int $id
	 * @param \WC_Product $product
	 *
	 * @return void
	 */
	public function new_product_set_defaults( $id, $product ) {

		$default = $this->get_product_defaults();
		foreach ( $default as $key => $value ) {
			$product->add_meta_data( $key, $value, true );
		}
		$product->save();
	}

	/**
	 * Set's initial Digital License Manager settings when publishing products from /wp-admin.
	 *
	 * @param $new_status
	 * @param $old_status
	 * @param $post
	 *
	 * @return void
	 */
	public function new_product_published_from_admin( $new_status, $old_status, $post ) {
		if ( 'publish' === $new_status && 'draft' === $old_status ) {
			if ( (int) get_post_meta( $post->ID, 'dlm_publish_flag', true ) ) {
				return;
			}
			$product = wc_get_product( $post->ID );
			if ( $product ) {
				$this->new_product_set_defaults( $post->ID, $product );
			}
			update_post_meta( $post->ID, 'dlm_publish_flag', 1 );
		}
	}
}

new DLM_Plugin_Product_Defaults();