hello all and ... happy new year !

I hope I'm in the correct forum.

Well, I live in Seattle.
I have a wife and 2 kids and we plan to go to Paris CDG twice a year (Summer + Christmas) using Air France (direct flight).
I would like to pay as less as possible

The wife and I plan to take a credit card with miles to reduce our tickets cost.
We spend around $30k / year on a credit card.
Do you know what is the best credit card/program for my family ?
I saw that Delta has an amex, will it work for this flight ?

thank you very much for your help