I Propose the option to collapse top-level discussions posts or expand all to view all comments in the app similarly to how the app Reddit does it. Once collapsed it should have the same marker indicating a new comment as before to let the students know there is something to review. From there you tap the post, and you can view all of the comments associated.
As with many other students, some of my classes have over 30 students who make individual posts with upwards of 8-10 comments per post. As you can imagine that is a lot to scroll through when trying to get to the bottom of the page. discussion board default settings discussion settings discussion feature discussion boards student