How can I access associated form data using JS (trying to build a widget)?

I have a widget page that offers a detailed view of a record of my Projects form. I have other forms associated with the Projects form and I wanted to display their data as well.

I have tried doing it like this:

document.getElementById("Assessment_Date").textContent = record.Site_Survey.Assessment_Date || "-";

But it is not working. Any guidance is appreciated. Thank you