I know they introduced support for customizing the HTTP pages, but don’t know when this happend.
If you use the default pages, it should be possible to use a pointer to program memory, which uses no ram at all. But the current implementation first copies all the pages to an array in RAM memory, which I think can be avoided.
Even if the users wants custom pages, I think most of the page content can still be defined as static const or constexpr and never be copied to RAM.