Sophisticated simulation
In case you wonder, Train Simulator 2019 and 2020 are the same game - Train Simulator just got renamed with the actual year. So the (2019 left-over) key sold here unlocks TS2020, as well as the three mentioned DLCs. Or if you have TS2020 already, it unlocks the three mentioned DLCs for it.
As for the game itself, I would call it a sophisticated simulation. The locomotives are recreated quite realistically, and the scenery comes with 3D-models even in relatively far distance off the track-sides. What seems a bit of a pity tho is that on many additional DLC routes all that 3D-scenery can't be seen much while driving - and while the game can be paused to fly around with the camera, it seems a bit too much content that sits outside of the context of game-play as such.