Hi,
I am a colleague of Ejay and I will be the one providing support.
Unfortunately, it is currently not possible to request link to another Google My Business account via the AdWords API. Based on this documentation, what you can do is creating business locations programmatically using the Google My Business API and linking them to Google Ads by creating the required feed objects. You may follow our blog for any relevant updates on this topic.
Regards,
Hiroyuki
Google Ads API Team