Hiding h1 tag for detscope or mobile version?

Question

Search Engine Optimization

Good day to all.
There is a site artpolitinfo.ru/libo-myi-ih-libo-oni-nas-videoesse...
A special header was made with the image of the post and the title of the post. In this case, the title in the detscope version is in the tag, <p>,and in the mobile version, implemented with media quyers, the title is hidden in <h1>because it is right next to the text.
1. Is this correct from the point of view of search engines?
2. Or do the opposite tag in the header <h1>, and in the mobile version in <p>.
3. Traffic from search engines sank by 15-20%, could this have affected?

Answer 1

h1 translates as first level heading. When parsing a page, the content of this tag can be regarded as the theme of the content of the entire page. p - paragraph. Can be regarded as "just text". 5 years ago it was definitely important. Now, unfortunately, I don’t follow the trends of search robot algorithms, so forgive me if I wasted my time.

Answer 2

Make h1 mandatory on both versions.
In media quyers, change the styles for h1 on mobile and desktop.
1) No
2) No
3) Yes