Set form field cookie and submit to checkout field – Not storing cookie

I’m having difficulty with the following code in that I’m adding it to code snippet plugin but I am unable to see the cookie being set in the developer tools after the form has been submitted. My understanding is that if the cookie is set then it should show the cookie name in the session within Developer Tools.

I’ve also tried to set the specific form from which I’d like the email field to be stored from, by specifying the form:

That’s my attempt and I think the autofill section is correct from what I have gleaned but the setting of the cookie itself so, by my estimation, the storing of the the email address isn’t being set as expected, therefore isn’t populating the billing_email field on checkout

Thanks in advance.