Like @JoshGrams said, you can click a topic to see latest in that category floated to the top. Also you’ll notice that topics in any list you’ve exhausted are “dimmed” in dark gray text, while those you haven’t read completely are darker black (or lighter white in a dark theme) and that seems to be separate from your tracking/watching prefs.
I don’t know if this behavior is consistent for other people, but I noticed that the “topics you may also be interested in” section at the bottom when a topic ends seems to push anything unread at me, so it is making the effort to guide you to new material.
In this image, the Raspian topic is not one I’m tracking, but it is highlighted on the Latest page (I’ve already read the two above it which were updated more recently)
Default Latest view
In “Playing” this post is at the top because it’s “latest” in the category