thanks for your suggestions!
I have the a2a cessna 172. It has indeed a good manual and as I read also from others an excellent implementation of the plane. It was good for me to learn, however for flying just once 30 minutes in the evening, it is too realistic, this is why I am often using the carenado 172rg.
So I also bought recently the King Air GTX90 from carenado. As they advertise and as I read in reviews: Less realistic than a2a, but easier to fly. However, here is the problem: The manual is really poor and as a beginner, it is quite hard to find out, what is needed to operate it. I could start without any problem, but after a few minutes the plane always loses height, I guess because I just started and did not go according the checklist.