So with your and Murtza help, it seems the correct tool should be: Visit Web Page. This makes more sense than a click, as its a page view (e.g. thankyou) that triggers the event - not a click i.e. registration. Noting that this is a virtual page view, needing the below code.
Munchkin.munchkinFunction('visitWebPage', {
url: '/virtual-page', params: 'x=y&2=3'
});
With this, I can say "all leads who got to page domain+virtual-page" push them into the process.