Colleges admit applicants, not high schools.
A top boarding school will have strong academics, opportunities to learn and grow as a person, develop leadership skills, have solid college counseling, amongst other things. But so can some other schools that aren’t boarding schools.
And when looking at college matriculation, keep in mind that this data from boarding schools is skewed by heavily hooked applicants - recruited athletes, legacy, fac brat.
Which choice is right for your kid, though, will depend on a lot more factors not listed.