For pulling values like that, I'd recommend two things. First, you can leverage the Developer Info tab, which is documented here: https://designers.hubspot.com/docs/hubl/how-to-use-developer-info-on-cms-pages. So from that Develoepr Info tab for your page, you could find the widget_data dict and see what's being outputted to the page. Then you'd locate your event_signup module and see what the values are there.
That helps me to see where to access module values. So all the parameters you need to access should be visible there. Let me know if this helps? I'm happy to look closer is this isn't detailed enough.