Well, if you come out with something Cartoony, people will say you're copying Unturned, and if you come up with something more realistic, someone will say you're copying Rust, just try to come up with something unique, maybe something like Cube World, but instead of focusing on the RPG aspects, focus on building, but allow for character upgrading/customization, along with plenty of things to do, You can have a crafting system or you can have it so people have to go hunting for the weapons and materials they need, just try something unique