Before proceeding, I did a re-check of the Block element itself and I believe we missed the “Remove container condition” condition setting.
Your Block element’s main container block “Remove container condition” was set to “No featured image”.
This is why the container wasn’t showing up. It’s because your pages don’t have featured image associated with them.
It should be set to “Choose…” to remove the condition so it always shows up. 🙂
I’ve applied it for you so it should be showing up.