another is regulatory requirements by jurisdictions to be able to legally assume a role.
This is exactly what I mean with “this depends on the country you live in”. Different countries have vastly different regulatory requirements. Taking UK as an example, you can call yourself civil engineer all day long without having to worry any legal consequences because there simply is no such thing as a licensing system for engineers.
Well idk the details in that specific case, this was just the first example I found. My point is, that different countries, states and institutions disagree on this matter. There is no universal rule that defines what you need to have achieved to call yourself an engineer.