The strategy I’m using now is to not waste too much money on mines and stuff, but rather upgrade your car itself, so you can start competing at the higher levels.
I mostly try to stay away from the initial chaos and indeed lag behind a bit, so I don’t get as much damage. Once everyone’s out of bullets, I just try to race as hard & clean as possible to get ahead. That seems to work quite well so far.
I’m not sure if the AI is indeed responding to your current position, but that could well be the case!