On the other hand, in Europe you are more likely to hear that "well, I'm not very religious", but many would culturally still identify as a Christian, and will held marriages, child naming ceremonies, funerals etc. in a church, and might even rarely, but occasionally go to church on a bigger festival (like Christmas) because it looks or feels nice.

I can't speak to Europe. But I have a friend/fellow grad student that moved here from the Caucuses who calls himself wholeheartedly orthodox Christian despite being decidedly along the above-described 'don't-care' to 'nope' spectrum about actual theological claims. Once called it 'an interface for dealing with stuff that every human has to deal with' loosely quoting.