Hi,
Thank you for reaching out to the Google Ads Scripts Team. Please excuse us for only getting back now as your message failed to be routed to our support queue.
Currently, it's not possible to setup your payment billing profile via Google Ads Scripts and said tool does not provide support to the Billing section of the Google Ads UI. I could raise a request for this feature to be exposed via Google Ads Scripts, but please take note that we would be unable to provide a definite timeline with regard to it's release. I would recommend you instead keep an eye on our Ads Developer Blog for future updates and latest announcements. In the meantime, you can reach out to the Google Ads Product Support Team as they are better equipped to provide assistance to your query. As an aside, would you be so kind as to provide your Google Ads account ID or CID which we would forward with the request?
Best regards,
Google Ads Scripts Team