Sam, the Medrash says that until the Cheit of Adam Harishon, the planets went much faster. That would suggest that time advanced at a different speed. Long day.
You also mentioned the concept of Bitzivyonam Nivra’u, that everything was created mature. I’ve heard people mocking this approach as intellectually dishonest, since why would Hashem deliberately create a circumstance just for the sake of tricking people. However, they are missing one point. The world is one big interdependent cycle. The plants need the healthy topsoil, which is created by microorganisms, which feed on other decaying matter, which come from dead plants and animals. Rivers are formed by the slow process of erosion. Large animals eat smaller animals who eat bugs that feed on bacteria. Hashem created decaying matter and everything else in all stages of the cycle.