Your Super 'site name' (located in Site Settings) identifies your site on your Super Dashboard. It is not shown as text on your pages, but Super also sends it to search engines and social networks as the name of your site (the og:site_name tag), so Google and link previews can show it next to your page titles. Use your real brand name there.
The page titles visible on your site are taken from Notion, not Super. So, the page titles that you create in Notion are the titles your visitors will see.
If you'd like to hide your page title with CSS, you can do so with this code snippet:
div.notion-header__content.no-cover {
display: none !important;
}