As a turnaround:
I’ve edited directly the file containing the Xbox settings
The file is located in:
AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\SystemAppData\wgs
There’s a folder with a lot of numbers.
In this folder, several subfolders with numbers.
In those, there are files with name containing numbers. One of them is a XML file containing all the settings in text.
Find the file, inside, you’ll find a section for the X, Y, rX, rY axis settings:
Edit the AxisSensitivity and AxisDeadZone to match your previous preferences