Carlos Sainz is at the centre of a three-team battle as he decides what his post-Ferrari future will look like. Sainz has known since the winter that he would be losing his seat to Lewis Hamilton. Audi have been determined to sign him from the outset. They will enter F1 in 2026 when they assume control of the Sauber team, and Sainz would be the ideal A-list signing to announce their arrival. The German giants recruited Nico Hulkenberg from Haas, but it’s been far more difficult to convince the Spaniard. That’s despite the fact they’ve tabled a lucrative contract even world champions Red Bull c…