Macmillan dictionary defines to be supposed to do something as
to be expected or intended to happen in a particular way or to have a particular result
Consider this expression
You are not expected to do this stuff.
It means that no one expects you to do this thing as this does not align with your work.
If I use supposed to instead of expected to
You are not supposed to do this stuff.
It might mean that if you do this stuff, this might be against the rules and you might be fined.
My question is that do supposed to and expected to mean the same thing? If not what are the context where they do?