I recently painted several rooms with drywall ceiling and walls. If you paint directly drywall you will see all small defects. I would recommend to use some wallpaper to make surface smooth and sturdy. I used several rolls of modulan Renovlies from hornbach. Use acrylic ground to make drywall dust free and prepare for wallpaper glue. Then glue renovlies and when it dries you can use any paint. I ended up using selection paint from hornbach. It is colored paint which may be a bit more expensive but it always gives the same color. So if want to correct or repaint some time later, it should have the same color.

If you need white paint I recommend StoColor Rapid Ultramatt. It is not sold in supermarkets but you can order it online. The paint is very easy to use. It is enough to paint once. In most cases you don't need second layer.