Thanks for reaching out.
If you're on Pro then you can simply add the Adsense code within the pro header and footer builder's text element, or content area element. Then assign that header or footer to the posts.
Then you can use the content builder text element for the Adsens code too.
And as for above comment area, that would require template customization as it needs to be added to comment template. Or simply use
the_content filter to add it, the problem is it may break the builder. Hence, it's more recommended to do it directly to the template.
And if you're on X theme, then you have to customize the template too since it has no header and footer builder. Maybe I could provide some instruction if you can provide more information on which part of the header, footer, content it must be displayed. The template has sub-templates so it must be specific. But to give you an idea of template editing then please check these