Hi,
I’m working on something similar to what you describe. We too have a pretty long sales cycle, and the deals could be worth a lot.
Would you put recurring events in that “Event Connections” property (Event X 2022, Event X 2023, etc.)?
If so, you would have to add options once a year when the event participation is decided. I don’t see that as a problem. As long as the options have unique names and you use a multi-select list, you should be able to report on, for example, Number of contacts collected from a specific event or Events influencing a specific Deal.