What a keyboard cannot be given
It is worth being precise about the thing this page keeps returning to, because the imprecise version — “a controller is better” — is both true and useless.
A game reads steering as a number. A stick hands it any number between full left and full right; a keyboard hands it one of three. The game is free to smooth what arrives, and this one does, which is why a keyboard car is drivable rather than undrivable. What no amount of smoothing can do is invent a value the device never sent. Deadzone and linearity controls operate on a continuous axis, and an axis with three states gives them nothing to work on.
That is the whole finding, and it decides what the rest of this page can honestly recommend.
What is worth changing
Bindings, and only bindings. The default driving plate puts everything a hand needs within reach, which is why the useful changes are usually about what you add rather than what you move: manual shifting puts three more keys under a hand that is already busy, and the assistant layer puts four more on the number row.
Both are worth adding one at a time, after the driving itself is comfortable rather than with it.
Where the measurement comes in
The counter that settles this is in the Input Lab. It counts the distinct steering values your own device produces while you drive. On a keyboard it climbs to three and stops, however long you keep going. It is a small thing to watch happen and it settles the argument better than a paragraph does.