I recently found out, the quality of the code in terms of SEO it is now somewhere very very far away. Ie I do not know the algorithms of search engines, but if this factor is present and affects the results, it is certainly not is of importance for the first ten factors.
As an example, the German HF query "Etiketten" - in the organic results of Google
in the first place by a wide margin is here but this page
. In second place - another page of the same site.
If you look at the code in the validator, you'll see 693 293 errore and warning. And nothing, as other factors are much more important.