YouTube uses the same mechanism as Twitter for displaying comments “under” a video. So, to extract all comments, a UiPath robot would need to, somehow, display a “next page” without a “next page” button. That two major Web sites are using the same “next page” functionality to display a list, makes me suspect the problem is generic and could crop up alot.
The following video has a (very) large number of comments so it’s useful for investigation and testing But what is a neural network? | Chapter 1, Deep learning - YouTube