Inspired by settings.pantheon.php; the idea is to use settings file to diverge configurations between environments.

settings.devforpantheon.php

<?php

/**
 * @file
 * Capacitype Overrides for Pantheon environment configuration file.
 *
 * This enforces logic that for all pantheon environments the following gets enforced :
 * a.) Except for live envinroment,  sending mail as logs in devel temp directory.
 * b.) Search API algolia : assets2algolia & topics2algolia are only enabled on LIVE pantheon envinroments.
 * c.) Enforce find-it active search index for live environment only.
 * d.) Enforce ask-it active search index for live environment only.
 *
 */

/**
 * Enforce mail logic.
 *
 * For all pantheon environments, except live environment, sending mail as logs in devel temp directory.
 *
 */
if (isset($_ENV['PANTHEON_ENVIRONMENT']) && $_ENV['PANTHEON_ENVIRONMENT'] !== 'live' ) {
  $config['system.mail']['interface']['default'] = 'devel_mail_log';
  $config['devel.settings']['debug_mail_directory'] = 'temporary://my-directory';
}

/**
 * Enforce Live Search API "search_api.server.algolia_capacitype_server" -- assets2algolia & topics2algolia
 * Enforce Dev Search API "search_api.server.algolia_capacitype_server_for_dev" xxassets2algolia & xxtopics2algolia
 *
 * Only on live pantheon environment that search api (assets2algolia & topics2algolia) are enabled.
 * For Non-Live pantheon envinronment the search api (xxassets2algolia & xxtopics2algolia) are enabled
 *
 */
if (isset($_ENV['PANTHEON_ENVIRONMENT']) && $_ENV['PANTHEON_ENVIRONMENT'] === 'live' ) {
  // $config['search_api.server.algolia_capacitype_server']['status'] = TRUE;
  // $config['search_api.index.assets2algolia']['status'] = TRUE;
  // $config['search_api.index.topics2algolia']['status'] = TRUE;
}
else {
  $config['search_api.server.algolia_capacitype_server_for_dev']['status'] = TRUE;
  $config['search_api.index.xxassets2algolia']['status'] = TRUE;
  $config['search_api.index.xxtopics2algolia']['status'] = TRUE;
  $config['search_api.server.algolia_capacitype_server']['status'] = FALSE;
  $config['search_api.index.assets2algolia']['status'] = FALSE;
  $config['search_api.index.topics2algolia']['status'] = FALSE;
}


/**
 * c.) Enforce find-it active search index for live environment only.
 * from find-it active search index, xxassets2algolia, to assets2algolia
 * d.) Enforce ask-it active search index for live environment only.
 * from ask-it active search index, xxtopics2algolia, to topics2algolia
 *
 */
if (isset($_ENV['PANTHEON_ENVIRONMENT']) && $_ENV['PANTHEON_ENVIRONMENT'] !== 'live' ) {
  $config['capacitype_search.appsettings']['active_index']['findIt'] = 'xxassets2algolia';
  $config['capacitype_search.appsettings']['active_index']['askIt'] = 'xxtopics2algolia';
  $config['capacitype_search.appsettings']['active_index']['fitFacets'] = 'xxfacets2algolia';
}

// Fix truster_host_patterns status error
if (isset($_ENV['PANTHEON_ENVIRONMENT'] )) {
  if (in_array($_ENV['PANTHEON_ENVIRONMENT'], array('dev', 'test', 'live'))) {
    $settings['trusted_host_patterns'][] = "{$_ENV['PANTHEON_ENVIRONMENT']}-{$_ENV['PANTHEON_SITE_NAME']}.getpantheon.io";
    $settings['trusted_host_patterns'][] = "{$_ENV['PANTHEON_ENVIRONMENT']}-{$_ENV['PANTHEON_SITE_NAME']}.pantheon.io";
    $settings['trusted_host_patterns'][] = "{$_ENV['PANTHEON_ENVIRONMENT']}-{$_ENV['PANTHEON_SITE_NAME']}.pantheonsite.io";
    $settings['trusted_host_patterns'][] = "{$_ENV['PANTHEON_ENVIRONMENT']}-{$_ENV['PANTHEON_SITE_NAME']}.panth.io";

    # Replace value with custom domain(s) added in the site Dashboard
    $settings['trusted_host_patterns'][] = '^.+\.capacitype\.com$';
    $settings['trusted_host_patterns'][] = '^capacitype\.com$';
  }
}