You may want to consider refreshing the page rather than using the back arrow.I didn’t explain my normal way of browsing very well
I always go to the new posts screen. I go through and open the threads I want to read, then use the back button to return to the new posts screen and go down to the next thread I want to read.
This software marks threads after you have viewed them. it "remembers" what you have viewed. Depending on your sort (like new posts) once you've read content and refreshed, that thing you just read will be removed from the list because you've already viewed it.
In some views (like the recent posts over the side bar) new content will be unbolded once you have viewed it.