The Apple 35+35 watt power adapter that comes with the newer MacBook Air s and can also be purchased separately is divided as you are looking for - it is neither the smallest nor the cheapest, but certainly very high quality. It is usually the case that two devices of different "sizes" (e.g. laptop + smartphone) are charged in parallel, so the asymmetrical division makes sense.

When I'm on the road, I have a smartwatch, a smartphone and a tablet with me. In the hotel, I only have one socket by the bed. The energy requirements of the devices are different. So the gradation makes sense. A lot of power for fast charging is actually not good for the battery. My wife has an iPhone that she charges overnight with the original mains adapter (5W). The battery still has a capacity of 83% after 5 years.