How to remove Chinese characters from Google account topics?

I'm not sure what you mean?
Can you upload a screen shot please?

I know that if I'm doing a search which involves visiting a few Japanese or Korean websites the Google ads are in Japanese or Korean for a while. (Same with russian, french, spanish, german etc)
Perhaps try clearing the cache 😉
 
WHen logged into Google, front Google page, the little '9 dots' shortcut next to the "Bell" notification icon, brings you to 'applications', which has an 'Account' setting, and, there is a language option within it....

If you are not logged in/signed on to Google, it will often default to showing the language from whatever local area you are in.....

(WHich I see a lot of, living in Japan)