Button does not align to the right

It depends on the contex of your design but this is the kind of setting you need to apply to the component instance and not the main component itself.

Unfortunately, this has no effect. The button should be directly next to the cookie banner when collapsed.

Yeah, you definitely need to look deeper at constrains and auto layout settings. Seems like right now you simply don’t understand those concepts

As Pavel said, you need to use auto layout.
E.g. http://clippp.co/sharex/nXKto3glLU.mp4

Thank you for your tips. I haven’t quite figured out how the autolayout works, but I have managed to get the effect right.