Saw your "Edit 2" just now.
You may try installing the language pack using the FOD and Language Features ISO as mentioned in my 1st post.
Download the FOD ISO:
https://software-static.download.prss.microsoft...
Mount it. Suppose the drive letter is F:, run this command:
Dism /online /Add-Package /PackagePath:"F:\LanguagesAndOptionalFeatures\Microsoft-Windows-Client-Language-Pack_x64_zh-cn.cab"
Dism /online /Add-Package /PackagePath:"F:\LanguagesAndOptionalFeatures\Microsoft-Windows-LanguageFeatures-Basic-zh-cn-Package~31bf3856ad364e35~amd64~~.cab"