Much thanks for all of the advices!
I was able to "test" the Clik Elite Contrejour 40 Backpack, renting it from an friend.
It is well built and able to contain everything you need for an 1-day trip. The reason, why I don´t buy it, is the price (300€) and it is not fine to carry, if your backpack is heavy equipped. In my opinion, the weight is not well placed. I feel that the backpacks pulls me back. I tried to repack and optimize the weight distribution. But this was not possible. Positive: The side opening for the camera and the opening on the carrying side.
The Naneu K5 is bigger, and has an extra "bag in the bag" for the Camera & equipment. Well built, very big. You can put his bag out by the side and carry it on your front side. Carrying is much better, when the backpacks is heavyly equipped.
Two reasons, why I sent it back:
1. The carrying-belt on my hips were not long enough for my stomach (172 cm, 84kg), so I was not able to close it in the front.
2. Minor reason: And if you open the camera case too wide, carrying in front of you, it happened that 2 lenses felt down. One of the straps, that should keep it from too much opening, was removed, when I pulles the case out of the backpack. The backpack is much cheaper. 200€. It would be worth buying, if the carrying belt would be able to be closed in front of my stomach.
Now I´m waiting for the Satori Exp from f-stop.