On-page SEO - is there any point in upside down layout?

Question

HTML

I've been reading about on-page SEO for a long time. One of the important points influencing good indexing and ranking was the placement of page content as high as possible to the beginning of the document. Usually there is a hat with a logo, a menu, etc. at the top. The header may contain a choice of the city, that is, in the code it is a huge footcloth-list. There could be a sidebar on the left, and after all that, just content. There are recommendations in the code to display the content first, and then everything else. And then in CSS, through position or margins, put the content in its place.
And now, dear experts, attention, a question!
Is there any point in worrying about it now? Is such an approach justified? Doesn't it contradict semantics? Or if it is correct to use < header >, < section >, etc. then it makes no sense to be perverted?

Answer 1

If there are identical links on the page, the PS takes the first one from the top.
2 identical pictures - similar, checked.
So look what you get from above on the site and evaluate the priority of the subject.
Yes, other things being equal, the content is better on top.
But if it's stressful - don't care, rely on semantics, it rules.