I would like to switch to Sketchup at 100% as an architect but I still need to draw also in 2D. Is it possible to use LayOut as a kind of simple 2D software? Thanks in advance.
You can do 2D scaled drawing in LayOut although I would do the drawing work in SketchUp since 2D views of the model (elevations, plans etc, can be created from the model and used in LayOut.
There’s no need for extensions to do drawing in LayOut.
but how do you manage symbols, etc…?
Layout has a number built in, and you can draw your own if you can’t find one that suits, and save them in a Scrapbook. As Dave says you can do the 2D drawing of symbols or plans and elevations, in either SU or Layout. The more complex the symbol, the easier it would probably be to use SU, and import them. For simple ones, use Layout’s 2D drawing tools, perhaps?
And why draw just a plan or elevation? Draw 3D and generate the plans and elevations from Camera/Parallel projection views and scenes.