They do that to reach 120fps on the XSX.
Thats why cars look like this in that mode:
Did you read that somewhere? DF also outright said they think its either a bug or a mistake, its not realistic to assume that this is representative of the power difference between the X and PS5. It seems like Series X is running the profile of a another Xbox System in terms of details, potentially the S but maybe even One X. All just speculation but nothing we've seen on paper would warrant this degree of difference between the platforms