Calling all Engineers: I've noticed that post 'normal' service (circa 10 & 20Km non DSG) the DSG is particularly crisp and performs well.
As others have said, it gets road tested on a proper service, and will also get all the fault codes cleared from the ECU memories. And if there are any ECU updates (to either the engine or the DSG, or both), then these will also be applied at the service. These will then set the ECUs back to their 'default' settings.
The Torque converter engages strongly and the cars throttle response appears crisp and lively.
Erm, the DSG does not have a torque convertor. I has a conventional friction clutch, albeit, a multi-plate clutch, and bathed in oil - oh, and there is a pair of them!

However after a couple of weeks of normal driving the DSG appears to get lazy....the torque converter is slow to engage on acceleration and de-celleration making driving far less enjoyable.
Can you please try and describe how the actual gear shift points are changing?
I've proved that this is DSG control/ ECU related by power cycling the car and the result is a return of super crisp performance and zero DSG Alzheimers.
LOL ^^^^
Seroiously though, if you are finding that the DSG worsens, then you must be driving very sedately!

Does anyone know how to stop the DSG auto learning as it's rubbish.
Don't think you can. Virtually all modern auto transmissions now use adaptive shifts.