I'd suggest installing the language pack offline using the FOD and Language Featues ISO.
See the example for Chinese (zh-CN).
https://www.winhelponline.com/blog/install-chin...
https://answers.microsoft.com/en-us/windows/for...
For Japanese language:
https://answers.microsoft.com/en-us/windows/for...
Standard Disclaimer: There is a link to a non-Microsoft website. The page appears to provide accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as PUPs (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.