A previous dev has suggested that the GTA 6 map must be smaller and a lot more densely packed. Having said that, as leaks have ongoing to trickle from Rockstar, modders have recreated the GTA 6 map in GTA 5's engine which gives a sense of its substantial scale. https://socialmediatotal.com/story4691414/5-tips-about-grand-theft-auto-6-wallpaper-you-can-use-today