MSFS 2020 is Not Detecting My Sidewinder Joystick

There are definitely sensitivity problems, but for the most part I've been able to make my controls feel similar to the way they did in P3D. I've found it's best to use only fairly small corrections to curves, but I try to add an "extremity dead zone" as large as possible but still get adequate control deflection. You'll find some aircraft will allow very large "extremity dead zone" - like 70 and some will only allow smaller like 20 to 30 and still maintain enough authority. For example, on the PMDG 737 I have an extremity deadzone for rudder (I'm using MFG pedals) of 70 and yet I still get full nosewheel deflection for very tight turns and plenty of rudder authority. You can do the same thing for your FFBII for aileron and elevator but may need lower dead zone setting. For many aircraft I still use a "sensitivity" curve, but rarely more than -20, -20 and usually more like -15, -15, or none at all.

I also find reduced "reactivity", anywhere from -10 to -30 or more helps cut back on the twitchy-ness of many aircraft - especially for rudder/nosewheel steering.