What Oracle may did to improve their performance so dramatically just in matter of few days ?
IMO there are two main components: foils and wing.
Maybe they managed to do what we did say before ? Tilt a wing sail towards the wind by tension windward steel cables ( or twist a wing at the top)?
That is what we do on windsurfing instinctively.
I looks that their boat is more vertical the Kiwis
another improvement could be wiglets at the top to release turbulence. Introduced not long ago to commercial aeronautics give several percent improvements..
If that works for gliders and sailplanes - must work for AC72 also