Use instanced static meshes in conjunction with material instances (the material needs to contain parameters for each modifiable property in its material graph workup). Each cube is 1 meter on every side. That’s rather big for that kind of game, and for a mobile game of that kind too. Try 10 units, so 1/10th of a meter, or 10 cm (a decimeter). Or halve it, so it’s 50 units / cube. I wouldn’t advise using scaling to modify the view size of objects currently. You need a base measure from which to build because it’s easier for calculations and correction. You probably didn’t have the right settings for the material that render correctly with the lighting setup used. Forget about where the camera is for now, as it’s merely a distraction from getting the meshes and their materials set in place and functioning in the lighting. The levels are using static lighting, so the lighting data getting baked in is remaining there, whether you change the camera setup or not. Don’t try procedural generation, as you’re inquiring about, as it’s limited to a number of caveats and lighting methods are more restrictive in terms of setup / functionality.
Modeling in Blender isn’t a bad idea, but it can introduce things you need to adjust for when importing to Unreal Engine. So, if going that route, research a bit for the particular models being made in Blender and how to properly export then import to Unreal. I could help with that a bit, probably, because I use Blender. But I’m not an expert in it, so I advise not relying on my suggestions or proposed solutions as a final answer.
The main objective should be to build one level and get that to function correctly in terms of lighting, structure, and materials. Try not to be concerned with physics and collision yet since if the other things aren’t working, then collision and physics is simply going to distract and present more problems to solve, and the project then becomes overwhelming and disparaging. Learn how to use Unreal to build with meshes, apply materials, and get proper lighting that you are satisfied about.