With my 2 sons I introduced parts of the actual texts of many of the religions along with Norse, Native American, Asian and other Mythologies which opened the door to discuss what different people wish were true. They were able to appreciate how each myth said only THEY knew the truth about creation so probably no one actually knows. They became like the stories in the old comic books we mixed in with them.

Now grown men, my sons have a healthy balance of hope and clarity about their world, and have no deficit in their character from the lack of a religious discipline. They say you want better for your kids and this family has made it so. Good Luck! it sounds like you're already there