I found this site: https://sapdesign-sandbox.webflow.io/half-on-half-layout
and it is exactly what I'm looking for.
A website in sections – one half fixed and the other one scrolling to its end and then both scrolling to the next section.
From the persona icon in the menue it might be page of @sabanna – unfortunately I did not find any topic/issue in the forum.
Maybe there is already something here I missed? Or someone can give me a hint how it was build.