Dynamically creating content on custom URL without getting 404

Yes, it´s totally possible, I just did that for a similar project some weeks ago.

I found this very helpful: How to pass extra variables in URL with WordPress

Basically the process is the following: Register new query_vars, fill them with life, pass them to a specific template which looks for them and then do whatever you like.

I did an integration for a REST-based web service with that. Live querying the information from the service, based on the ID I pass like this: mysite.com/events/1567612313/

Works fine.