In general when you add attachments to a build array, then add the cache metadata in the same place:

$build = [];

// attach libraries and their drupal settings
$build['#attached'] = [...];

// add the cache dependencies for this data
$build['#cache'] = [
  'contexts' => ['url'],
  'tags' => ['dtm_global'],
  'max-age' => 60,
];

If you want to add cacheable dependencies of objects to the build array, you can use addCacheableDependency(), see https://www.drupal.org/docs/8/api/render-api/cacheability-of-render-arrays

Now sharing this with other modules is no problem anymore, drupal builds a page with hundreds of different build arrays like this, all from different modules.

In general when you add attachments to a build array, then add the cache metadata in the same place:

$build = [];

// attach libraries and their drupal settings
$build['#attached'] = [...];

// add the cache dependencies for this data
$build['#cache'] = [
  'contexts' => ['url'],
  'tags' => ['dtm_global'],
  'max-age' => 60,
];

If you want to add cacheable dependencies of objects to the build array, you can use addCacheableDependency(), see https://www.drupal.org/docs/8/api/render-api/cacheability-of-render-arrays

Now sharing this with other modules is no problem anymore, Drupal builds a page with hundreds of render arrays like this, all from different modules.