Designing something on an architectural level really isn't always a data structures and algorithms problem. Take the web, for example. REST isn't complicated, but it does the job and it opened up more possibilities than any other invention since timesharing.
As other commenters have noted, choosing an architecture for a system may have more to do with vision, common sense, and even imagination. And the web is such a great example of this, maybe the classic example. As you probably know, it's possible to write a webserver without having a clue about fancy data structures or algorithms. It's the imaginative composition of pre-existing features that creates the architecture.
Another example would be the extensibility of Emacs through elisp. Consider the notion of hooks which essentially allow utility functions to be customized by the user. It's a purely architectural concept.
Or the Unix philosophy: small utilities that read and write text, linked by pipes. Really no algorithmic complexity to it at all.
It feels problematic to me that you are saying to someone that they "need to stay far, far away" from some aspect of computing. It's a kind of gatekeeping. Sure, an outfit like NASA needs to make sure that they don't have amateurs writing their systems software. But in the industry more broadly, people have to be given permission to pursue whatever interests them. It's important, for diversity and the invention of new applications, that "differently able" coders aren't told, by intimidating stereotypical computer science types, that they don't have the aptitude to architect a useful system, or that it's "a rule" that people with their skills will just create problems.
Vision and a perspective that differs from the norm are a lot rarer and potentially more valuable than the ability to apply software engineering principles. Architecture, in the broadest sense, is precisely the area where these "outside the box" contributions are likely to be valuable. Consider the invention of the Wiki. It came out of the pattern language world, it was a hugely beneficial innovation, and it has almost zero data structures/algorithms complexity behind it.
I'd even argue that the examples of pitfalls that you list are more clerical matters of systems programming than cases where architectural design principles are lacking.
(And even the professionals who can reliably grind out working code for large systems can get the architecture spectacularly wrong, as the case of the X window system: http://web.archive.org/web/20170920104011/https://minnie.tuh... )