It's a hard question, I was lucky to have some private school but for my high school years it was public and a complete waste. Religion for the schools I went

It's a hard question, I was lucky to have some private school but for my high school years it was public and a complete waste. Religion for the schools I went too weren't that enforced, but I would say ask other parents, there should be a good tour of the school included, and then check out the clubs they offer. "Better" though, is hard. I would just review how they teach STEM - interview the teachers with open ended questions and see how they respond. One big PLUS though is the networking, private school, the peers/kids are usually from "better*" (for lack of a better word.) off families so that could mean better success, even if religious. It's hard to quantify it, but the friends I made from my private school days helped me tremendously learn so many different things - how life is different for the truly well off, to community, and "success". It sounds odd writing it like this, but in the USA many kids in school are there because it is compulsory and it is not a profit center, it is a cost center, bigger classrooms per teacher, smaller campuses, food not healthy, and draconian rules like no water bottles in class or other. Of course it does depend per school, but those pain points about public school, can be taken to see if you can find a proper private school. And if you do, I would get the most of your dollar and do the parent events too - meet the other parents and strike bonds that may really last your childs lifetime.