For example in forza, the game plays engine sounds based on how much we press the button. Are there different sequences of clips ? If yes how do they blend so well ? Or are they synthesized dynamically ?
There are so many parts to it as well - when the great shifts, when you suddenly slow down at high speed, when you suddenly accelerate from stop. They all seem very realistic.
Different studios take different approaches, I know when Polyphony digital was making Gran Turismo 7 they dramatically changed how they were doing audio by actually bringing the real cars into a dedicated recording studio. This isn’t the video I saw a few years ago, but it’s similar.
To my knowledge they may have been (still?) the only studio doing it this way.
SCS, devs for Euro Truck Simulator 2, records sounds from the actual vehicles as well.