Does privacy policy need to be in all languages an app supports when uploading to app store?
It is not mandatory to provide privacy policy translations for all the languages your app supports.

Additionally, as I can infer from your post, since your app's primary language is English, privacy policy text in English should suffice.

If you still have concerns or have specific questions, as a paid developer program member, you can seek help from Apple Developer Support and get answers for specific queries.