I've learned a lot when it comes to making city covers, and the biggest lesson I had was not to start with such a big project as your first build. Looking back, I realized that I was way too ambitious with my first cover, and it ended up being a laggy mess that I had to split into 4 parts (and even then, it was still laggy as hell and a nightmare to make updates). So I decided to make my second cover a lot smaller, just a simple abandoned planned city in Central Asia. I'm a lot more proud of this cover than my last one, since with the smaller scope I was able to improve the quality a lot and it looks a lot nicer now. You can find it here if you want:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3181107192&searchtext=kazakh