One way to do this is to use the HTML insertion area like Advanced Options > HTML Insertion > Pre footer code box
Given you cannot use widgets in there, you should use a Show post shortcode in there to display the posts you need.
To create show post shortcodes, you need to install Weaver Show Post plugin (https://wordpress.org/plugins/show-posts/ ).
It lets you create filters that determine which posts to show and how to display them, and gives you a shortcode that you can insert in the HTML insertion area.