TYPO3 Core

TYPO3 seo extension should feature the functionality to create a sitemap index file on root level.

Example configuration for a page with 2 languages:
https://www.mydomain.com/de/
https://www.mydomain.com/en/

Both have a sitemap:
https://www.mydomain.com/de/sitemap.xml or https://www.mydomain.com/de/?type=1533906435
https://www.mydomain.com/en/sitemap.xml or https://www.mydomain.com/en/?type=1533906435

rootPageId: 1
base: 'https://www.mydomain.com/'
languages:
  -
    title: German
    enabled: true
    languageId: '0'
    base: /de/
    typo3Language: de
    locale: de_DE.UTF-8
    iso-639-1: de
    navigationTitle: Deutsch
    hreflang: de
    direction: ltr
    flag: de
    solr_core_read: '%env(SOLR_CORE_DE)%'
  -
    title: English
    enabled: true
    languageId: '1'
    base: /en/
    typo3Language: default
    locale: en_GB.UTF-8
    iso-639-1: en
    navigationTitle: English
    hreflang: en
    direction: ltr
    fallbackType: strict
    fallbacks: ''
    flag: gb
    solr_core_read: '%env(SOLR_CORE_EN)%'
errorHandling:
  - errorCode: '404'
    errorHandler: Page
    errorContentSource: 't3://page?uid=20'
routes: {  }

routeEnhancers:
  PageTypeSuffix:
    type: PageType
    default: /
    suffix: /
    index: /
    map:
      /: 0
      sitemap.xml: 1533906435

What i cant do:
https://www.mydomain.com/sitemap.xml or https://www.mydomain.com/?type=1533906435
Call this page (because there is no configuration for /) and get a sitemap index file containing the path to both language sitemaps. Why cant i configure this? Because the path is for languages only. And i have configurated my languages already on /de/ and /en/.

Whats the problem:
Google Indexer will look at domain/sitemap.xml to improve page indexing.
Google Indexer will loot at robots.txt if there are any rows with "Sitemap: path/to/sitemap.xml" definitions

1. Generate a robots.txt by typoscript to tell google where to find the sitemaps = faild to same reasons
2. Let my default language listen to / and the english version on /en/, but then the index sitemap would only contain sitemaps in default language.

Versions:
TYPO3: 9.5.13

Am i missing something, or is this a needed feature to maintain the current and future sitemap pool for all domain/language combinations without static htaccess redirects?