I understand your doubts and I would try to add some of my thoughts. I may not be able to answer some. Looks like we have a very similar view about events planners' job. I do call myself project manager because I am
I run different type of events and the price will be different on the type of event.
1St the price of the ticket is set up to cover the costs only
2nd- the price is set up based on the value the attendees will get which will be higher than just the costs. This events will bring profit.
With regards to planning.
Once I know what kind of event I will deliver and the content I would then know what kind of sponsors I would see at the event. I also want the sponsors to be of a value to the attendees and vice versa.
The budget will be set up depending on the type of event as well.
I think- don't overthink it. I often do and it slows me down.