wrong using Flats?

Hello everyone.

I have something wrong with the flats in the calibration process.
I use Flats, Master Dark and MasterFlat for calibration.

Because it doesn't do what I want properly, or I'm just a bit stupid to understand it correctly

here the comparison of the only strached output pictures

• first:

without APP - nice flatted

Cal+Stack by DSS, some streched & Color balamced by PS

• second:

with APP - only pollution gradients?

cal by DSS, then integrate wirh calibrated Lights only

• third ---> MY PROBLEM:

only used APP (cal, stack, normalized, integrated, streched) - strong vignetting? 

and the Flat:

I dont removed any gradiends

It is made up of 43 x 300s. RGB frames (ASI071MC Pro) Gain 90, Offset 65, -15°C near fullmoon

I left all settings at default

Maybe someone will recognize what I'm doing wrong

Thanks a lot 🙂