This is pretty cool, does it scrape Instagram? A lot of events where I live (Toronto) are posted there and not many other places. It's a real problem if you don't want to spend time on that app.
I know this is currently a paid service you're trying to make happen and the scraping part is a reasonable amount of effort, but if you wanted to make the data source public, you could publish community.lexicon.calendar.event ATProto records and it would be very cool. At the very least, you could ingest it as a data source!
There's hundreds of events happening every week but finding them takes a lot of time.