Create page templates like the ones in your theme folder but through a "DX Templates" menu in your Admin dashboard - HTML, JS, PHP supported
The plugin uses the eval() PHP function that evaluates a PHP script on the fly. If a hacker reaches your admin, he would be able to write any form of PHP which could affect your site and database.
However, if the hacker has an access to the admin, he could 1) delete everything and takeover your site, or 2) upload a custom plugin of his that does the malware work.
Your full HTML as it would be in your page template file. HTML, head and body sections, meta tags, some content. It would replace the entire post/page resolved from the site.