Ah I see.
The Block content you’re using is for Element type – Page Hero so the Block element assumes that whatever you’ve added to that block is part of the Page hero. So it makes sense why you’re getting 2 containers. 1 was added as a page hero while the other is the actual content.
It’s not ideal to do this. Contents are not supposed to go to the Page hero section.
You should do this the other way around where you add the page hero as content rather than adding the content as part of the page hero.
If you want to modify the content area you’ll have to do another Block Element with element type of “Content Template” and add your page hero in it.
Or just modify your existing one from Element Type – Page hero to Element Type – Content Template.