Thanks for your help!
I deleted the unnecessary material data. I applied geometrical imperfection already with the shape of the model. I entered the keypoints for the areas to be meshed in a half sinus wave curvature.
I will try out the stabilize option. Can you recommend a value for the energy-dissipation ratio for this problem? And would this value also be appicable to other modells with the same shape but other sizes?
And how should i interpret the results, especially the applied normal force, since it seems to be higher?