Workaround for copying records (besides creating an API/JavaScript

Hi All,
I have attached a few images that explain what I am trying to do. I have a Template Event and Template Event Role objects. When creating a new Event, the user can manually put in the roles, or they can select a template. If they select a template, I want to be able to bring (copy) all the child records from Template Event Role to Event Role.

I have attempted a work-around but am missing one key aspect and looking for some advice.

THank you

@Charles - quite a bit to unpack here. It’s the sort of thing I’d need to see as I’m much better looking at the schema. I’ve sent you a DM as using Make is likely a pretty simple solution.