Jake,
If switching to another internet connection source doesn't help, try this:
Download Microsoft-Windows-LanguageFeatures-Fonts-Jpan-Package~31bf3856ad364e35~amd64~~.cab from my OneDrive temporary download link.
- Save the file to a folder named C:\FOD\
- From admin Command Prompt, run: dism /online /add-package /packagepath:"C:\FOD\Microsoft-Windows-LanguageFeatures-Fonts-Jpan-Package~31bf3856ad364e35~amd64~~.cab"
and
Dism /Online /Add-Capability /CapabilityName:"Language.Fonts.Jpan~~~und-JPAN~0.0.1.0"
- Press Enter.