So you have adopted a new theme and would like to have more control over your archive pages? You can always change things with a bit of coding. Archive Control for WordPress can also help. It is a plugin that lets you make changes to your archive pages. You will be able to change titles, featured image, content before/after and order.
The plugin lets you display custom content before or after your archives. These pages can be shown randomly, by date, or in many other ways . You can disable and enable various options from the Archive Control Settings page.
The plugin leaves styling of your pages to you. It is a free plugin.