I have been experimenting a little with the sensitivity of the rudder in bot large and smallA/C in FS2020 recently, and have noticed that I am seeing complete rudder reversals at full extent in many different aircraft, but especially the GA ones. In the Zlin it is a nightmare, even using very little rudder inputs it goes everywhere but where I want it to go.
Update to this, I just reset all setting to default for the rudder, and it is even worse.
If you , as in my case, twist the joystick quite quickly, the rudder reverses almost every time before it reaches its full correct deflection. It seems to do this even if moved fairly slowly…
Go into the controller’s properties in Windows and see if it’s behaving normally there. It sounds like it might be a controller issue and not sim-related.