Hello Reynald, these files are the input for import in 'Widget Importer & Exporter' plugin and 'Customizer Export/Import' 

If you can provide wp admin access we can import demo data free of charge. This will give you a snapshot of our live demo you can start customizing from.

Hello Reynald,

you configure that section through page or portfolio item options. So when you edit the item (classic 'Edit' and not 'Edit with Elementor') you scroll past the editor area and you see the page/portfolio item options panel.

the settings are inside the 'Hero Section' tab in that panel.

Hello Reynald,

you disable the hero section in every page by first, disabling it in page options and then second, disable the default hero section containing the page title.

About <div class="cd-index cd-main-content"> we do not recommend to remove it (or change it) since is the root of the container that is filled and being loaded in ajax page transitions.

it can be found in header.php (path relative to root theme folder)

Yes, you cannot actually hide the hero section for portfolio items, they must have it; it's precisely because ajax page transitions from portfolio templates to individual portfolio pages.

But for regular pages it should be fine.

To add a revslider - disable the global (default) hero section in customizer -> general settings and then disable the hero section in page options. Use the rev slider at the beginning of the content.

Ok, at this point is it possible to send us wp admin access in a private comment so we can have a look?

Apart from that setting (which you did, that's good) you need to set 'Display Hero Section' on and off in page settings

https://prnt.sc/YQFsqcNSsuAa

Hello,

Well, I get it however it's for us to guess what is wrong unless we are able to inspect it. So if you can upload it somewhere online so we can inspect it (provide wp admin access in a private comment)?