You can check with Adobe support Team for new language code. For existing check https://developer.adobe.com/document-services/docs/apis/#tag/OCR/operation/pdfoperations.ocr here.

Refer https://experienceleague.adobe.com/docs/experience-manager-dispatcher/using/configuring/dispatcher-ssl.html?lang=en for dispatcher.

https://developer.adobe.com/document-services/apis/pdf-services/  explains how to update PDFs using API.

You can try a sample response for Reports here: https://developer.adobe.com/analytics-apis/docs/2.0/apis/ to see if you can get segment details.

While most projects can be deleted, sometimes a project is related to an application you have published and, therefore, cannot be deleted.If a project contains an API submitted for approval (status: In Review or Approved), then the project cannot be deleted.If an App Builder project has been submitt...

Can you directly open the system console and see the CQ link configuration?

https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/assets/manage/assets-insights.html?lang=en is helpful for Assets insights.

https://experienceleague.adobe.com/docs/experience-manager-65/deploying/deploying/data-store-config.html?lang=en is quite helpful for data stores.

You can try using Search Boosting to get the desired results:https://experienceleague.adobe.com/docs/experience-manager-learn/assets/search-and-discovery/search-boost.html?lang=en

Can you check AEM logs to see why it is failing?