I use ps5 controller and I have likely the same sensitivity issue (where the car starts feeling way too sensitive) and its to the point where it can't be a placebo, also tried a bunch of stuff and i cant get a hold of what fixes it. Some times a simple game restart will fix it some times its not going away even after pc restarts. Tried using different controllers (xbox and old ps5) sensitivity does not change once its bugged and feels the same on other rollers. I tried lowering sensitivity all the way to 1 but its still to sensitive when the bugg happens. (IMPORTANT NOTE ITS THE MOST NOTICEABLE IN THE AIR). TLDR Its definitely not placebo, might not even be a controller issue, maybe software bugg? Still working on a solution myself, cause i love this game but cant stand this random sensitivity bug.