My kid was lucky enough to have a similar choice (Brown, Duke, Harvard). It felt daunting, but In hindsight forced my kid to be highly introspective about what they wanted both during their college experience and what post college ambitions they wanted to pursue.
It was hardly an exact science. Harvard felt too IB oriented, Duke not strong enough in entrepreneurship and Brown the perfect flexibility of curriculum and dedicated start up resources. He chose Brown after visiting all schools twice (we were lucky to be able to do that). In most cases it was a feeling not fact based but different schools did have different resources. Ultimately it was subtle differences and reasons to say no as there were so many reasons to say yes to any of these schools.
In hindsight any of these schools would likely have produced similar outcomes and or experiences but he benefited from the adult responsibility of having to make a meaningful and consequential decision. Once done he never looked back from what we could tell so similarly I hope your “pain” will soon pass.
I will also highlight just how important alumni network is (all three schools are great). At least for my kid who has sourced multiple 7 figures of funding for his startup largely through alum and contacts of alum and or the “Ivy Network”. Most of his friends found jobs by connecting with former alum via Linkedin and networking. Linkedin means accessing alumni networks for kids at elite schools.
Even when kids don’t access the initial opportunity directly through alumni they are able to leverage alumni contacts into insights and opportunities. As someone whose kid has first hand experience with the schools you are comparing, I would be careful not to under appreciate the value of alumni network.