@jess2716 – you ask a very important and interesting question. Google provides a wealth of data to help you optimize your stories.
1. As @luckynasan mentioned about the GA Events. You can also see how visitors moved through your story. Ideally, we want them to start and complete the entire story, but this is not the case. Knowing which page(s) the visitors drop off is important so you can work on improving the engagement and getting visitors to stay longer.
You can see this in GA also, by clicking on an Event Category > then Event Labels which shows all the pages in your story. They are actually numbers 0,1,2,3,4, etc…
Another really great place to see amazing data is Google Search Console under Discover menu option on the right.
This will open a whole new world. You’ll see the power of Google’s AI in placing your content in front of a likely audience.
Hope this helps.
Terry