It's a bit of a complex interplay. If the FAA were finishing their investigations very quickly, SpaceX could be more aggressive with their testing. But on the o

It's a bit of a complex interplay. If the FAA were finishing their investigations very quickly, SpaceX could be more aggressive with their testing. But on the other hand, as SpaceX gets a better read on how long the FAA might take, they time their readiness to when the FAA will be done. For example, here they waited ~1 week between Starship being ready and done with a wet-dress rehearsal. If they knew that the FAA would be finishing earlier, they'd try to get through the WDR earlier. But since there's plenty of other development and testing to do on the ground, they just do that in the meantime. The FAA delays were more of an issue around IFT-1 because they really couldn't proceed on much without knowing how all the big systems they built would perform, they would've been working blind (and considering how the launch infrastructure needed further strengthening, doing too much more without that data would've probably been a waste of money). That isn't really the case now, while they wait on the FAA they can focus on the payload bays, refining the control systems, building the second launch tower etc.