This actually fixed it for me, but since I use Windows 11, the wordings in the system is a bit different. For me, it's:
- Go to settings, go to "Time & Language" on left bar, then go to "Language & region"
- Go to "Administrativa language settings" under the related setting section
- There will be a new window that popped up, showing two sections with the title "Welcome screen and new user accounts" and "Language for non-Unicode programs". There will be a button that says "Change system locale..." in the latter section.
- Click that and change it to Japan (and yes, as Sairruah have mentioned, you'll need to restart your PC)
If that still doesn't work, then you probably have to change the region under the "Language & region" into Japan as well. Hopefully this helps!