Alternatively: Move the page
To return what's underneath back to the top, we need to delete the page. But if you've put a lot of work into making the page and you want to keep it, the alternative is to move it.
The Site Builder version is being shown because there is a Site Builder page mapped to the current URL.
If you want to keep it, AND have what's under it, you can move it to another URL that is empty.
We do that by going to
SITE BUILDER -> PAGE CONFIG -> PAGE SETTTINGS