in the Customizer > Layout > Container – the value set in the Container width is how wide the page is. This includes the sidebar.
In Customizer > Layout > Sidebars you can set the % of the container width to be used for the sidebar.
So you’re site is set to 1100px of which 30% (330px) is the sidebar.
Setting the container width to 2000px is an easy way of forcing the page to fill the entire browser view. Which is not something i would recommend for a blog. Your current settings provide the right reading width.