Missing publication datetime, you can get it from "post-item__date" after removing other tags and words. "Subtitle" contains text that not intended for this purpose

Using an article image for the cover loses the caption.

This is not a <figcaption> tag, and the image for this caption is not present, because it's gone into the header.

cover is missing

cover is missing

unnecessary sign up

empty p and unnecessary hr

Extra, empty, <p> tags

Irrelevant empty paragraphs.

Irrelevant empty paragraph.

I guess first image should be a cover

The caption for this image has jumped to the cover image.

The cover image does not have a size-full class, it only has size-large. That and the bold paragraph indicate that it's supposed to be part of the flowing content, and should not be moved elsewhere.

there were nothing of this kind in original article

The chosen image from the middle of the text is clearly inappropriate for the cover. It's even not first image in the article or image_url for preview

it's very difficult to undestand what is what in the article without horizontally centered alignment and with the same style of all strings