At least on iOS ad blockers are integrated into Safari so any native app using the Safari View Controller will use configured content blockers. That's why Facebook and others will continue to use the legacy web view.
Yeah which Facebook doesn't use for rendering newsfeed ads. I'd imagine that google does the same thing for its native adverts. Also, I'd imagine that all banner adverts displayed in third party apps are native as well. Disclosure, I worked on the main Facebook app.
