I’ve got a 2l diesel DSG kodiaq SE spec.
so far (5500 miles) it’s returned 42mpg overall but I can get over 50 with more reasonable driving. But to be fair I do drive it hard. I pay for mileage at work not fuel.
The DSG is very good in comparison to many autos I’ve driven (over 35 years) , will change down when needed and is usually in the right gear. I often leave it in sport mode though so it changes up a bit later. I’d certainly recommend it over a manual.
The boot in the 7 seat loses a fair bit depth over the 5 seat but only you can make that decision.
I would say though that the extra seats are really only suitable for children or small , flexible adults!
Regarding luxuries. The se is perfectly serviceable. AC , climate control, good media system. What more do you need?