The Last War: Hacker survivor

Hello, I work with games a year, I started this project a few months, the project is a survival game where level design is in rio de janeiro - brazil. The main characters will be the father and son who tries to survive amidst the zombie apocalypse.
I finished the first step of the map, made all blocks of it, I put interactive models with the programming, I followed the steps of uncharted, wanted to do something in high quality, I have infrastructure for that, I wanted to buy a lot of things from the megascans bookstore, I’m in doubt because most to stay with a good quality the map is 4k, I am thinking of using 4k maps in the scenario where the character will pass and the models that is far from the character, the map being 2k along with the LODs,

Sorry if I wrote something wrong, my English is not fluent