Even at the last zoom level before iFly overlays the RealView, the sectional is getting zoomed beyond it's native resolution so it's starting to pixellate slightly. But one thing you can try if you really want to go farther (it works on Android; dunno if iOS is different): Use the +/- buttons to zoom to the tightest zoom level that doesn't include RealView. Then, use your fingers to pinch-zoom closer. As long as you maintain the pinch-zoom, you'll see the even-more-zoomed-in sectional without the RV overlay...the RV won't appear until you lift your fingers.
But it'll just be the same resolution, only with bigger pixels. If your vision is good enough to pass a Class III physical, I don't think you're going to see anything more using that technique than what you can see at the last zoom level before the RV shows up.