I think what might work for you is using a dynamic URL like this:
and using creating a field called eventId that will populate the dynamic part of the url:
Depending on your use case, you can configure the page to do whatever fetching you need to do with the eventId in the url, maybe it will pull in data for a Data Model with the same eventId, or maybe from your own third party API. Take a look at this forum post for some examples of cool stuff you can do with dynamic urls and data models:
https://forum.builder.io/t/dynamic-blog-article-using-next-js/3613
I highly recommend you check out these docs for more information about this topic:
https://www.builder.io/c/docs/dynamic-preview-urls