Creationists tend to needlessly complicate things.
Here’s the simplest way to deal with this alleged time scale problem. The one evolutionary relationship that most gets creationists hopping mad is that between humans and chimps. So was there enough time for these two species to arise from a common ancestor?
This blog post from Larry Moran goes thru the calculations, and shows that the time that would be required for the number of mutations that separate us from chimps is exactly in the range of what would be expected, based on the observed mutation/fixation rate and the amount of time that scientists believe has elapsed since the existence of our common ancestor.
It’s important to note that this is based on all the mutations being fixed by neutral drift. It doesn’t even require any beneficial mutations. That whole issue is a red herring.
Is there any reason, given this information, that one could reasonable doubt that there has been enough time for evolution to happen?