The DOM timeline you describe would be pretty straightforward to create using a MutationObserver [0]. It's available in all major browsers.
[0] https://developer.mozilla.org/en-US/docs/Web/API/MutationObs...
[0] https://developer.mozilla.org/en-US/docs/Web/API/MutationObs...
We do this on a different side of our product which we try to come up with test coverage from how your users use your app.