The answer depends a lot on the radio in question, in my answer I'll talk about computerised radios that we tend to use for racing. The radios that come with 'ready-to-run' RC cars often don't have all of these adjustments, but usually still some basics. For cars, the radios used are usually a wheel and trigger design rather than a gamepad or 'stick' style radio. Although in the minority there are pros, amateurs and in-between who use stick radios for cars.

First, we adjust 'sub-trim' or 'trim' settings to centre the steering. This is because every vehicle has different requirements for installing the servo, and even in the same vehicle a different servo may have a slightly different alignment of the output shaft.

Next, we set endpoints to match the physical limits of where the steering can travel. This is often a different value at each side of the steering. This sets the total range of movement of the steering.

The next adjustment is called 'dual rate'. This sets the percentage of the total travel of the steering. So rather than setting a steering range in degrees, we set the steering based on percentage of total travel. Often the vehicle is easier to drive with less than 100% steering range, so this is reduced down to a drivable setting.

There are many other settings that can be adjusted including 'exponential' which can give the sticks more or less sensitivity along their travel, adjustments for how quickly the steering movement will happen, adjustments to delay in response from radio input to steering output etc.

While it is possible to have the steering become less sensitive at higher speeds using telemetry, this is not common. Usually the travel of the steering is the same at low or high speed. However, there are many other physical adjustments to the vehicle's suspension and geometry that will effect the steering.The car can be physically set to slide more as you say, or may understeer under full power but then be more responsive off throttle. There are often more things to adjust on these cars than their full scale counterparts!