Creating an infinite runner, and I was wondering if the player continues to move towards infinity, would there be a point in which the transform position’s number would be too great in which unity crashes? If so, should I switch it where the environment moves instead like a treadmill?
So simple answer: Yes, do the treadmill.
More precise: No afaik your game will not crash.
More more precise: Instead your game will look like garbage at some point. Why you ask? Because the larger your positions become, the more imprecise your positions will become. A position is stored in floats. A float has a size of 4 bytes. In general it automatically assinges the most possible precision after the comma so that your number is the most precise given the amount of memory. But the larger the number → the less space there is after the comma. So at some point your float will not be able to have any decimal places at all. All your models will become extremly warped and wobble around. The speed will not appear constant anymore. So before it crashes it will become unplayable.
However depending on the speed the time you have to play might be really really really long.