There's a new video on the videos page: 5 minute Tutorial - Parallel Rendering of Many Layers
It shows how having many layers in a map isn't going to slow down the rendering, and how to use folders in the Layers pane to bundle many layers into a single tab.
it is insane to see how many CPU you have during the test compare to my old PC !!
at the video say "it is not excessive desktop" ( i5 3350p compare to Ryzen 9 3900 X 12 core Processor )
Show off/on all the directory drawing in once by one click make me really think of Photoshop layers !!