Track end-to-end from Google campaign to booking of a meeting

I would like to track a Google campaign to a booking of a Hubspot meeting end to end.

Current the meeting-booking-tool is not supporting integration of the GTM code in its header. With this you cannot track the funnel of that 3 step process (Appointment selection → Data entry → Success) in detail.

So the request is to support the GTM integration into meeting tool as well as it is supported in CMS and landing pages.