Thank you for the detailed reply. Awesome that you spent the time to detail it for anyone who finds this thread! I agree Zapier is a better solution for now.
Just to update: I received an update from Hubspot saying their internal team is aware of the Hubspot events - Facebook CAPI not working and there has been a communication issue which is why the knowledge base articles inaccurately make it seem like it’s possible to optimize ad delivery towards these lifecycle stage changes.
They are working on a fix but it’ll likely be 2024 by the time it actually works. They are first fixing the form fill event - FB CAPI.
BR, Tero