@ScarDuck14 McLaren, on the base game before updates were perfectly capable of being in the midfield ranging from 6th - 10th every race.
If it is impossible to reverse the changes to the car. Then the only option left is to implement a stat reduction of Lando especially by at least 3-5 points across all his stats (Overall, race craft, experience, pace and awareness). Hopefully that should slow Lando down to where it better suits the abilities of the car. Not where he is dragging it from 4th best to consistent pole positions.