You could copy the relevant part of the current HTML source code and paste it all into a custom HTML block. You might want to first paste it into a common text editor so it’s easier to do search and replace operations to alter media references to relate them to the new site. After patching the references, then copy/paste into custom HTML.
The resulting page would not be editable using the usual blocks interface, but the content would at least be correct as-is. This would not include the current page’s CSS, so the page will look very different even if the content is identical. You could also copy the current CSS and paste it into Additional CSS (which might be hidden by default, but it’s there). The problem is the CSS could interfere with the normal WP CSS. Ideally you’d pick and choose only the relevant CSS and modify the selectors so they only apply to the one page.
In short, there’s no easy automated process. It will involve some manual effort. In some cases, it might be easier to custom design a new front page, even if the textual content is roughly the same. This could be a good opportunity to update the home page appearance to have a more modern look and feel.
