Once you or any Admin users logged in, you will get the published site. To change the portal site, the Global Filter selection option is provided to manage all the builders’ data and templates. The different sites can have different pages.
So, you can change the portal site from that site drop-down selection and according to that, you can make the changes in the builders.
Multiple sites management helps to display the different types of site data (Lists, Forms, Pages, Templates, and Menus) as per the site configuration.
As you change the Site, you will get the page builder data as you have configured for that site.