For those who are just starting to consider private schools for their young kids, my first piece of advice is to visit all the schools on your list and really check them out in person. Published test scores and other stats only go so far. I started researching schools as soon as it was confirmed that my wife was pregnant. My initial list of schools that I picked based upon online research wound up being 100% different than the schools we really chose after visiting them.
A series of in-person visits is really the only way you will gain a comfort level for the specific people who are going to have a huge influence on your kids inside and outside the classroom. Besides teachers, you'll have coaches, fellow students and their families all playing a big role in your kids childhoods. We have been very fortunate to have our three in schools filled with like-minded families. That means their friends and the families of those friends are the kind of people you are glad to have your kids hanging around, doing sleepovers, playing on sports teams with and eventually dating (my kids are not quite old enough for that yet). These are the people who become the volunteer coaches on the sports teams, chaperone field trips or coach on cheerleading squads, etc.
You must also decide if you want a serious religious component or not. We quickly realized that some "Christian" schools don't really walk the walk. We wanted the real deal, with chapel, Bible classes, regular prayers and a Christian perspective infused into the curriculum. In our school's application process, you must submit letters of recommendation from you pastor indicating that your family regularly attends church services and is involved with church activities. Other Christian schools do not require that and take the stance that they will evangelize non-Christian students once they are in. Many other schools are just going through the motions or are purely secular (and usually woke).
Our kids are not enrolled in one of the 2-3 schools whose names everybody recognizes (St. Johns, Kinkaid, Strake), but they still receive a superior education compared to even those public schools that people tout as being near the top. We've had kids transfer in from well regarded, suburban public schools and struggle to catch-up academically in even the on-level courses.
Also, just because a school doesn't send every graduate to an Ivy League institution, doesn't mean that a self-motivated student wouldn't get into a highly competitive university. Our school sends a high percentage of each graduating class to A&M and Baylor, but we also send kids to MIT, Stanford, Rice, Tulane, service academies etc. each year. The point of all that is to say that published stats about previous graduating classes don't guarantee any particular result for your kid. You have to look deeper than those stats.