I'm currently cleaning up my personal blog and I'm trying to make the HTML adhere correctly to HTML standards. The blog structure is simple. I have a home page that links to blog posts and a page for each blog post.
For the blog post pages. I'm not sure if I should use the <main> or <article> tag to wrap all of the content.
I would either use
<html>
<body>
{ heading, navigation, etc. }
<main>
<h1>{title}</h1>
<time datetime="{publish date}">{human readable publish date}</time>
{content}
</main>
</body>
</html>
or
<html>
<body>
{ heading, navigation, etc. }
<article>
<h1>{title}</h1>
<time datetime="{publish date}">{human readable publish date}</time>
{content}
</article>
</body>
</html>
If I read the HTML specification for <article> correctly,
using <main> seems to be the better option because <article> is meant to separate independent self-contained parts of an HTML document while <main> is meant to indicate where the main part of the document or meat of the document.
The reason I'm hesitating is because <article> works with the <time> element to allow me to specify when the post was published.
From MDN (https://developer.mozilla.org/en-US/docs/Web/HTML/Element/article):
The publication date and time of an element can be described using the datetime attribute of a element. Note that the pubdate attribute of is no longer a part of the W3C HTML 5 standard.
(Note that your two examples create a different document outline.)
Use both. The elements serve different purposes and work fine together.
<main>
<article>
</article>
</main>
If you can only use one element for some reason, go with main, because the use of the heading creates an implicit section (where article would make this section explicit), and all article-related features (like address and bookmark) also work if the body is the nearest section. Note that there is no time-related feature for article anymore (early HTML5 drafts had the pubdate attribute, which offered such a feature, but it got removed).