How to create a full width box

I’m just started using Gutenberg for the first time. The page I’m creating is not the full width of the computer screen; i.e., it has a maximum width. However, I would like to add a section that for that section only overrules this and uses the full width of the screen. How can I do this?

As I understand it, this should be possible by creating a Group and then setting that group to “Full width”. However, when I do this, it still has a gutter to the left and right, so it doesn’t seem to work. Is this not the right way to do this?

I use a clean install of WordPress 5.6.1 with the free Astra theme.