Those UVs are not good. They may work okay for painting directly on the surface in painter, but they'd be a nightmare to work with anywhere else. A good UV layout will be easy to parse on its own, should have a logical arrangement of shells based on material type and large rectangular pieces should be straight and axis…
Hi! Based on this example, I think it should be fairly easy to trace its shapes with primitives in a modeling application. Doing this a few times, you might get more proficient with the application and do certain subjects there. Cleaner topology will certainly make UV-unwrapping more pleasant. Out of curiosity, how are you…
Well, others have pretty much covered it in the replies above : by doing everything in a voxel sculpting app (which can indeed be quite fun) you're pretty much shooting yourself in the foot if your goal is to get to clean and efficient game assets from there. Now there are indeed ways to convert what you have to ingame geo…