html5 – How Important Are Tags for SEO?

What do you think? Seems to me that adding <main></main> tags around your page content tells Google what content is most important and unique to this page. Google then knows to only look at the content and links within the tags for indexing. It can largely ignore <header>, <nav>, <aside>, and <footer> content. Anyone agree? Anyone able to cite an authoritative resource on this subject?

I know WordPress automatically adds <main> tags around page content. Seems Google likes WordPress sites, say over Weebly, Wix, or SquareSpace … or other drag n’ drop site builders. I wonder if it’s partly because WP is good with HTML5 semantic tags. I even see WP drag n’ drop editors (like Elementor) omit HTML5 markup tags by default. And likely the developer is unaware and doesn’t go back and add them. Are those sites hurting their SEO? Does omitting HTML5 markup, specifically <main> make it more difficult for Google to index and understand the page?

I’m surprised I can’t find much on this topic on the internet.