Logitech G920 + Euro Truck Simulator 2 Is Weird

[Aurora]

Could someone explain why my wheel behaves weirdly when I change settings of the force feedback in-game? The only way I've managed to get my wheel to act like a wheel (lol) is to put the Force Feedback Gain on about 1% and stiffness on about 5% - the rest is at 0%. But I'd like my wheel to do stuff that a wheel actually does, for instance getting force feedback from the engine, terrain and such, but if I activate those stuff the wheel just does random things. My drivers are up to date and so is the Logitech Software.

Here's a video of my problem:
https://www.youtube.com/watch?v=zygb4iIuCtM