I assume you are already using the "useheading" option (set it to "always") so that the first headline becomes the name to be used here.
In (rare) cases when I want to override that, though, I like to use a very low (h5) heading as the first line of a page, and use an h1 heading just underneath. In this case the DokuWiki system pulls the first (small) headline as the page name, and the visitor will still see the larger heading as the main headline.
Please note that this has some accessibility implications (as the hierarchy of headlines is broken on the page), but for specific cases, like on the main landing page, this is probably OK to do anyways.