If someone says to you their name is "John" you know how to write it. Foreign names might be weird sometimes (hi Ireland) but usually they're simple.
In Japan you have to ask everyone how to write their name because there's no standard way of spelling. And every character has (completely) different pronunciations depending on context https://www.thejapanesepage.com/tag/kanji-pronunciation/
I was more referring to the phonetic alphabet and standardized spelling part of your post, and not to the Japanese part. That's why I proposed Korean as the language to satisfy your requirements, as English does not, as exemplified by the name John, which is pronounced [jon].
Yes, but to a much, much lesser degree
If someone says to you their name is "John" you know how to write it. Foreign names might be weird sometimes (hi Ireland) but usually they're simple.
In Japan you have to ask everyone how to write their name because there's no standard way of spelling. And every character has (completely) different pronunciations depending on context https://www.thejapanesepage.com/tag/kanji-pronunciation/