I just spoke to Google Ads technical implementation team. They confirmed that, as of now, the only way to get Enhanced Conversions to work is if the form fields are passed as URL Parameters to the ‘thank you’ page like this: mywebsite.com**
Please update HubSpot forms so the form fields are passed in this way. The Google rep told me that every other major platform (squarespace, webflow, etc) already does this.