It kind of sounds like you want to go to these places because of the brand. You’ll need a more specific and compelling argument than because you want a Boarding School experience. That’s not getting you into Exeter. As has been said, you need a materially different presentation for it to have a different outcome.
There are a lot of good schools. If you want a boarding school experience at a great place, expand your search. If you only want to apply to two very hard places to get into, well I suspect that will come out (again) in your application.