Google recommends to use "www.recaptcha.net" in your code in circumstances when "www.google.com" is not accessible.
https://developers.google.com/recaptcha/docs/faq
Other platforms and their modules provide a toggle or configuration option to replace the recaptcha URL to www.recaptcha.net in countries where google may not be accessible (such as China)
https://www.drupal.org/project/recaptcha/issues/2993365
https://wordpress.org/support/topic/add-option-to-load-resources-from/