I have noticed a very big Throttle deadzone (using Fanatec V3 pedals) which is about 15-20% big (lower throttle deadzone). I've rechecked the pedal calibration and tried out other sims. The problem only occurs in raceroom. Also checked the lower deazone settings again, everything 0. I can also see the deadzone in the menu, the throttle input starts at 15-20% to be visible.
Rebinding the assignment solved the problem. Thank you so much for your help, now I can breathe again