Are you still looking for the difference between Train Sim World 2 and its successor Episode 3 released on September 6 on PC/PS4/PS5/Xbox One/Xbox Series? The environment, with crazy dynamic weather, and the training center, which allows you to enjoy the game 200%.
Here is a video to show you the work done by Dovetail Games on the training center. More discreet but still present, dynamic weather provides a more general environment, which also benefits from an improvement in climatic phenomena (volumetric clouds, lightning effect, snow, etc.).