Typically with a 'section' the first line inside it for me is a heading. So on the outline there are no 'unnamed sections'. Save with 'nav' and other content blocks, I usually find that there does need to be a heading in there anyway.
So Grid does not care what the elements are, however, that form fieldset won't work in CSS Grid and there may be a couple of other edge cases. Now here is the important thing to know - have too many nested divs and it makes CSS Grid very difficult, almost pointless.
So, imagine a form. You can have just label followed by input, label followed by input with some submit button at the end. This can be put into CSS grid and styled beautifully with no effort. It goes responsive effortlessly as well. There is nothing to it.
But then, in real life you are working with some legacy code where there are divs around each form element and divs grouping the labels and the inputs and an outer wrapper with spans around the required field asterisks, everything with class attributes on it.
It is hard to imagine if you are used to that type of markup that you don't need any of it!
But that is the case. You can write ultra lean HTML.
Then when it comes to actual content, e.g. a blog article, you realise that the WYSIWYG paradigm is doing us no favours. It has no structure even if it looks okay.
So I use the article and section elements to just get my writing neatly organised, with headings at the top of each. This is more about just writing content neatly than presentation.
The div makes sense if you are copying stuff from old tutorials, but it never makes sense with content, but it sneaks in there. It is so baked in with things like the Wordpress Gutenberg blocks thing where some people have staked the whole company on new ways of writing out of spec bad HTML. If you check the manual you will see it is the element of last resort and just isn't needed with CSS Grid layout.
Before CSS Grid layout you did need the div to make wrappers for centering stuff. But now you don't. But people have got so used to using it that it has got stuck in the mindset, a groupthink that will look silly in a decade or so.
I also style the elements, never needing classes. But with no div wrappers these are all sensible looking to me but would horrify someone doing BEM notation. Here is an example that gives you an idea...
body > footer > nav > ul {
display: grid;
grid-auto-flow: var(--footer-nav-ul-auto-flow, column);
grid-gap: .25em;
justify-items: var(--footer-nav-ul-justify-items, left);
padding: 0;
}
So that is for some responsive footer links, they go across the page on desktop and the other way on a small screen. Best practice would say that I add 'footer-links' as a class to the footer links. Best practice says the 'body > footer > nav > ul' selector is 'too complicated' as it uses four rather than three (max) selectors. But that is how I like to read my CSS these days, with no preprocessor, no compiling, just spelt out.Now this example is not a portable component but that is the point, the document structure is relatively flat and quite predictable.