So this probably isn't helpful to many people but I figured I'd throw in what I found when it comes to the niche situation of someone wanting to search the whole forum but exclude the headlines. I was running into this situation with Fallout, as I previously mentioned, but searching in just a specific subform wasn't the best solution because there's both a video game series AND a TV Show.
But this is how I ended up doing it.
So in the advanced search, if you click "All Forums" or "Discussion" it will include the headlines, because I guess it's technically located within Discussion. But that means if you click everything EXCEPT those two, it'll search the entire forum but the headlines section. So you click all four subforms displayed under Discussion and then all the other sections further beneath it. On mobile they have checkboxes so it's simple, on desktop you have to hold CTRL while clicking and you can multi-click.
So it'll look like this:
I'm sure this is obvious for staff and those who search a lot but it took me a bit of experimentation to get exactly what I wanted. But with this you can easily exclude the headlines section from a forum-wide search (works with title searches too of course). So if anyone is looking for that exact thing without having to do multiple searches, hopefully this helps. lol