Man, where did you get that chivalry is not Christian? I am just not sure what to do with a claim like that. I have literally read the early chivalry manuals and they are definitely Christian manuals on moral conduct for soldiers written by Christians for Christians and full of Christian values.
I agree that life in the modernity was soft for a while, compared to starving because of a drought or or something. But that wasn't because of kings or knights. That was because of technology and we definitely have better tech now. Culture is another question.
I get that you might not like the idea of going to church if you are not a Christian and that's fine. Christians believe in free will. I don't think it was ever a wide spread thing that anyone was forced to go to church by anyone other than their parents, and parents do need to make decisions for kids.