all in a few thousand years

Actually, it is worse than that. We have no reason to believe that rapid speciation was happening since recorded history. So actually the time available is not much over one thousand years. And there is a second problem, which doesn't really arise in the evolutionary theory but does in the creationist 'equivalent': there is a built-in 'tick of the clock' since inheritance can only happen when the child reaches maturity. In the case of beetles, that's quite a short time, but in the case of say red kangaroos, that's round about three years. Either we assume the creationist form of evolution ran differently in Australia to Europe, which is yet another thing to be explained, or in the case of the marsupials it all happened in something like 250-500 generations. Every one of which must be a viable creature in its own right. Moreover, each must find a mate that is sufficiently similar that they are capable of interbreeding and the offspring inherits the relevant adaption. That isn't a problem for scientific theory because the number of generations is extremely large and the changes each step are correspondingly tiny. Limiting to around 500 steps is a problem.