^This.

A350 is suitable for long, thin routes. JFK is neither one of those. It is high premium demand, and only the 77W has P (La Première).

If you really want to fly the A350 to/from JFK, you can fly LH to MUC or AY to HEL, and make a correspondance to Paris or whatever other destination. Or you can fly AF from EWR but AF switches appareils frequently on most TATL routes so even then you should not bank on the initial résa.