Forget Layers altogether, particularly if you are used to ANY other drawing system, as you have noticed they don’t work as supersets. What is critical is to have everything as groups and components and then as the drawing builds have groups of groups and components containing further components. Eventually after a years work the drawing will be huge and you will find that it suddenly become uneditable because it will take seconds to pan, zoom redraw etc (even on a 5.6GHz 32G SSD Gaming system and 500 quids worth of Nvidia !) . That is when layers become essential so you can distinguish between ‘drawing’ and 'presentation. Ie you turn off all trees, bushes, electrical & plumbing fittings, hinges & doorlocks, roof tiles etc and only turn on the detail when you need to make the video.