I have seen tutorials in which the textures of the buildings are pre-rendered, especially the part of the bump maps. Of course, if the type of lighting is changed at any time and from where the light comes, you have to redo this whole process so that it does not conflict with the lighting of the scene. They also make more basic versions with less mesh, the most similar to the final buildings. but its use will be to capture only the shadows (in a different layer than just shadow capture) and finally the buildings furthest away from the location of the camera are placed versions with much less mesh and few polygons and the closest buildings and first planes if more care and complexity is put into the mesh, all to try to manage the scene to reduce memory consumption or make it be captured in parts in different render layers, separate layers for reflections and speculum are also done that is possible with the refractions also all these renders are captured separately and then finally combined with the compositor, I have not yet found tutorials in Spanish about it. So that they are updated, even if it is to version 2.80, but I am sure that in English there must be very good tutorials of this type to better squeeze the limited resources of a modest PC. Basically you separate the elephant into smaller pieces that your pc can handle. I am still at a very basic level without even being able to make a good uv's map but I long to reach this point and be able to do what I am mentioning here with knowledge and expertise, by the way I saw it in a tutorial for blender 2.76 or 2.79 and I am not experienced enough to do a conversion of this knowledge to the current version of Blender. waiting for what happens first or that they do a tutorial about these memory management tricks with the layers and the compositor on low-resource PCs and combine all the renders with the compositor obviously with the limitations and complexities that must surely be presented when doing this type of thing in Spanish or that I develop and accumulate the necessary knowledge to be able to do it myself. I don't know what happened first.💪 ✌️ 😃