I've thought and read a bit about getting initial users but never done it successfully so I can't offer much from experience. That said, reading your experience with your list of 82 prospects, I don't see where you demonstrated value to them. Demoing value is different from merely "explaining" value.
One of the classic missteps is expecting people to inherently "see the value" of what you're building. Nobody just sees the value like you do. You have to demonstrate it. Show them how their life will be meaningfully improved with your app.
Couple that with event organization being a two-sided problem. Any successful product needs to offer value for both organizers and attendees. You've mentioned time-saving for the organizer - great - but what does an attendee get out of it? For both parties, how are they coordinating currently? Is your app clearly 10x better for both sides?
Assuming you've got all the above checked off, then I would start with a simple strategy: Organize some events with your app. Be your first user, and make the friends you invite your second, third, and fourth users. Did your app make organizing easier? Or did nobody actually RSVP when you know they would face-to-face?
Remember, introducing an app into any experience inherently adds friction. So your default starting point is that you're actually making it harder for organizers to get RSVPs on the books. Your app needs to offer enough value to make up for that friction.
I would expect there'll be a grind until you hit a point where people are more likely to attend events you organize through the app, and those attendees decide to use your app for their next event. At that point you're viral. But until that point, you've got an app that makes things worse for the user compared to their current alternative.