3.0 V6 TDI – Acceleration?

Hello! Unfortunately, my faithful battlehorse (Audi A6 b4 2.5 TDI) is approaching his retirement after 13 years and 450 000 carefree km. So next year a new car will be due. I thought that many money I saved with my A6 to invest in a Phaeton 3.0 V6 TDI GP3. Once there would be the expected service costs – are they really as bad as you read everywhere? 2-3k Euronen + Diesel a year would be ok, but partly you read real Horrostories wa I live in a rural area. In the case of the large number of “Best Agers” who no longer dare to drive faster than 60 km/h on the country road, acceleration is a decisive criterion. Is the 3.0 V6 TDI comparable to the A6 b4 2.5 TDI? Purely from the power and mass of the Phaeton, the acceleration would have to be better?