Yoast, who I am sure you are familiar with :)
Says this about SEO at https://yoast.com/wordpress-seo/#headings
Although most themes for WordPress get this right, make sure your post title is an , and nothing else.
Your blog’s name should only be an on your front page, and on single, post, and category pages, it should be no more than an .
Your sidebar shouldn’t be crammed with and ‘s either etc.
When I look thru a Vantage theme page and search for h1 tags, I find
– ie the site title has an h1 heading
– – ie the page/post title has an h1 heading
So this is not really that good for SEO.
Is there a particular reason you have chosen to make both the site title and page/post title h1?
Is there a way to change this?