Pretend_Imma_logo
A header receives a role="banner" if it is the closest header scoped to the body element.
A banner landmark typically contains global information to a site/application and can house other landmarks like navigation and search.
There is no heading element in this header, and that's a-ok. The h1 is far more useful setting the primary topic of a document, than it is housing brand identification.
The main landmark wraps the primary content of a document.
articles are not landmarks. However, they may be surfaced by certain screen readers, especially if given an accessible name.
VoiceOver + Safari on macOS will surface articles that have been given an accessible name in an "articles" router menu. You can give an article an accessible name by setting an aria-label or aria-labelledby="..." attribute.
Using a role="region" creates a generic sort of landmark that can be used to promote an important section of content, that would not be better classified under one of the more specifically named landmarks.
The usage of regions should be limited, as adding more "important" areas to a page conversely decreases the importance of other areas of the same page.
Another way to create a region landmark is by providing a section
element with an accessible name.