We use the custom code to organize the discovery meeting journey in HubSpot. Our business process looks very simple: A lead books a discovery meeting => a respective deal is created
Unfortunately, a standard workflow didn't work cause the deal's ownership was assigned incorrectly, it created multiple deals in some cases, it didn't consider if there was an open deal associated with the same project, etc. that's why we needed to use the Operations Hub. Now, there is another issue that we cannot fix, it turns out that when a deal is created, it is not associated with a discovery meeting that triggered its creation. Our engineers state that they cannot associate those entities because there is no object association between Activity and Deal. Is there a way to associate those entities by using a code?
The way I understand objects and activities in HubSpot is that activities are always associated with one object.
This article explains the basics. So in your case the meeting is associated with the contact, you then link that contact to with the deal that is being created. So by associating the contact and deal object, you would get the reference back to the meeting (activity).
My first suggestion would be contact workflow -> meeting booked enrols -> deal gets created but you said you run into issues. When a deal gets created manually from a contact recod you have the option to associate previous activites from the with the deal associated contacts or company to the deal you are creating (see screenshot).