Just out of curiosity: what makes the lightweight version, well, lighter? as far as i can tell from your video, there isn't a big difference from them. (but again, i tend to not notice details)
so specifically, the original version uses Unity's High Definition Render Pipeline while the lightweight version uses the Universal Render Pipeline, which doesn't have as many features and is meant to work well on any platform. If you compare the two side-by-side, the difference is pretty big, especially when looking at the sky, the fog, and the areas that have lighting