ultimately, i think that if my kids decided that they wanted to go to church, i would take that as a kind of a red flag that i'm doing something wrong. what is missing in their developing epistemology that i haven't plugged in? why are they seeking faith over reason? how do i address this?

are they just curious? well, maybe we can sit down and read a book about religion together, instead.

here's a good one for that:
https://www.amazon.ca/Outgrowing-God-Beginners-Richard-Dawkins/dp/1984853910

but, i mean, you need to listen, first, and your reaction, in the end, should be with the intent to be informative without being controlling - to give them the information they're asking for, but not to try to direct them towards any specific conclusion.