Create an admin page from template
Absolutely, it's quite straightforward.

You'll need a path for the page:

function MYMODULE_menu() {
  $items['admin/foo/bar'] = [
    'title' =&gt; 'Foo',
    'page callback' =&gt; 'MYMODULE_admin_page_callback',
    'access arguments' =&gt; ['whatever makes sense'],
  ];

  return $items;
}


A theme declaration:

function MYMODULE_theme() {
  return [
    'funky_admin_page_content' =&gt; [
      'variables' =&gt; [],
    ],
  ];
}


Your function to build/get the content. Note that you could also put this in a template file, see hook_theme() for more details.

function theme_funky_admin_page_content() {
  // Build your HTML, return it as a string.
}


And your page callback:

function MYMODULE_admin_page_callback() {
  return [
    '#theme' =&gt; 'funky_admin_page_content',
  ];
}