For mechanical bust: If you have a beast of a PC and do not think you need to learn proper uv layouts since you will probably apply for texture artist / ?general 3D artist positions? You could do the quick lazy method of just clicking unwrap all <- for the low poly version and letting zbrush do all the work for you then…
Like this one. It is composed of many scattered parts. Do I need to disassemble UV for every screw or wire? For example, such a game character model. With many details and different materials, how do I decompose UV?