Accessing content type fields

I'm trying to build a variant of the listing block (peopleListingTemplate ) to list a kind of user's business cards. For this I have created my own content type people in whose schema there are, for example, the fields fullname, office, address, phonenumber and email.
I proceeded as in the training with the eventListingTemplate

Through the console.log(items) in the code, I can see the two items created as a test when accessing the listing block, but only a small number of fields for each item that I can access. (@id, @type, description, title, url ... )
I also get the same information via the react developer tools in my browser.

I've already searched the plone training site, the documentation site, and the forum here, but I couldn't find any information on how to access the other fields in the scheme.

Maybe someone could give me a little hint that puts me on the right track