How do different roles and responsibilities, scopes relate?

I’m working at a pretty huge multinational company delivering systems consisting of multiple HW components and their embedded software, who’s not that experienced in SW development. We have System Architects, System Engineers, Software Engineers, Software Architects, Developers, Test Engineers differentiated in our V-Model based process landscape.

I’m curious about the industry’s opinion where do those roles have their scopes, what are the overlaps?

In my head, a System Architect decides how the overall system is connected to the world, interconnected and where the different features live, what inputs they use from the multiple components.

A SW architect is responsible for designing the software features (once he knows where those live, and what is the environment, what are the inputs).

System/SW Engineers are terms for people eliciting requirements with customers/architects on their respective levels.

Developers develop, test engineers test (unfortunately unit testing is officially not a responsibility of the developers, but that is changing).

We are pretty much not caring about this process, and everyone does a bit of everything (developers creating system requirements for example).

What is your experience, what are the responsibilities behind these “tags”? How do they overlap?