Here is the setup, you mean the noise modifier in the graph editor, right?

It is a texture, I found out that by changing the texture interpolation it works. I don't even know what it is, you wanna explain?

Thank you so much for the detailed answer, that was a "on-point-introduction" into the topic and pretty much summed up all my questions. I will do my research. That png is not a good format suprises me, because every tutorial I have seen so far uses png for rendering, but I am still a noob

I figured out that it was because I put a displacement on the plane

yes, do you think its because of that? I will try without

That's perfect, thank you so much! :)

Thank you very much!