I have been using the same Simplified Chinese account across multiple devices, including Mac and iOS, for over two years without any issues. Recently, however, my Mac device has suddenly switched to Traditional Chinese with English support, while my iPhone is still functioning normally. I am unsure of what could be causing this issue and how to resolve it.
I have tried troubleshooting by assuming that I accidentally logged in from an external region using a proxy, and clearing my proxy settings in AM. I have also restarted my system and tried logging in again, but the issue persists.
One possible solution I have considered is that it may be related to my Family Sharing group, where a family member's system language may have been set to Traditional Chinese, causing the issue.
I have attached an image for further reference.