Right joystick is incredibly sensitive

Okay, I tested it. If I barely move the joystick, it won't do anything, but it's such a miniscule dead-zone, it's not really worth mentioning; no game would ever need to be that sensitive. The only reason it's there in the 1st place is because the bottom
plastic edge of the joysticks have to move down (as you push the joystick up, down, left, or right) to touch the sensor inside of the controller to activate the signal so that it knows you're moving the joystick - that's all; that would be true for ANY controller.

it won't be listed as Joystick Sensitivity under Controls.

in game settings look under Gameplay for Look or Aim Sensitivity.

I too have exactly the same problem described - and it's driving me daft.

It seems that it is not uncommon and that the issue is within FS 2020 rather than my Thrustmaster HOTAS One joystick.

I have tried everything that I can think of to find a fix including re-installing FS and joystick drivers.

Does anyone have a solution for this vexing problem please?

I believe I have solved the issue with the Thrustmaster USB Joystick, and probably any other joystick that is acting "too sensitive". I had this problem until I figured out that I had only mapped "Aileron Left (Roll Left)" and "Aileron Right (Roll Right)" to
the "X Axis", and I had failed to set the one that simply says "Aileron Axis". Once you set ALL THREE of these, you should be good to go. For the record I did set the sensitivity to have a 20% dead zone and sensitivity to -40%. I plan to continue tweaking
these values, but I was finally able to control the aircraft. Try this.

Change the deadzone on the Joysticks, having the deadzone too low will cause drift because they're ultra sensitive

There are models of controls such as the elite 1 and 2, which allow you to change the sensitivity of the joysticks