Your viewer's list will be only available for you for 48 hours after you have published a story, but there is a thing you must keep in mind, stories are still ephemeral and they will get disappeared after 24 hours when they are posted.
This means, that the list of G story viewers is available for you to see for another 24 hours after the story is removed. The stories viewer list is not public, hence only you and only your team will have access to the list, and you can make the stories last longer than 24 hours on your profile, by adding them to the highlights.
Using the steps provided below you will be able to convert your instagram story into a highlight. You have to first click on the + button on highlights on the screen after which you will be asked which story you will like to add to your story.
You can also choose a cover photo for your story highlight, along with which you can also enter a name for your story to identify your highlight.
And, if you are seeking some ways how can you access instagram content anonymously then, read the given below blog.
Blog: https://getassist.net/access-instagram-content-anonymously/
Great topic