“lightmaps” and “baking light” and I’m not doing any of that.
Why? more than likely part of the issue is due to lighting. having lightmaps is required for meshes, your probably using ones that are auto generated. as for baking lighting well that just means that the engine will calculate how the light in the level should be behaving and will more accurately light objects in the level. so building the lighting would be a good idea as well. unless you are using fully dynamic lighting you will have to bake eventually.
really i just dont understand why you would just write im not doing that. why would you not want to? what could it hurt?