Hi there,
so excluding the Blog, Single Posts, Header ( Nav and logo ) and the site copyright footer bar. All of the content is edited in Elementor.
The hero sections – the Background color is set on the Elementor Section, the Images are added using the Background Overlay setting, this allows them to have the multiply effect.
In regards to your ‘logo’ i am seeing the Site Title of Hellequin Systems on your site. So maybe browser caching?
For the Blog page – the Hero element is set in Dashboard > Appearance > Elements. You will also find other elements there such as the single post custom hero which uses a GP hook.