I have raced this version of Tatuus in a competitive league for a while now and after gathering the exact same impressions from other drivers, I conclude that this car is the worst of the Tatuus pack. All of the cars seem to share very similar underlying physics, but this model stands out. Firstly, the range of adjustments in the setup is not done well. When you drop the rear wing to minimum and front wing to maximum, even after making sure the the aero from underside is working properly, you end up with an aerodynamically understeering car. It is not possible to create an oversteering platform with any combination of settings. The fastest times in the competition are achived with setups, where we take off rear grip inentionally, for example adding +30kpa rear tyre pressure and setting the rear toe to NEGATIVE 2.0 degrees. Even if you then end up with a crooked car that rotates immediately in corner entry, the innate slip angle of the tyres prevents the rear from coming loose, as if it was rubberbanding to the ground. Also, the geometry of the front axle means that any further steering angle only digs the car into the ground and bogs it down. The result is that the car loses a whole dimension of driving on 4 wheel slip angle, which is what rFactor 2 is all about. Instead you end up with an iRacing-ish experience of just guiding the car around and waiting for the understeer.
Have you adjusted rear suspension position and brake bias? Brake bias is way too much on front and default rear suspension position isn't optimal. https://forum.studio-397.com/index.php?threads/tatuus-f3-t318-rear-suspension-position.63709/ There's also link to Tatuus workshop manual which contains info about those rear settings.
