Look at those people, especially those in civil law and criminal law. Most of them are proficient in Japanese or German.
Of course, it is best to be multilingual and be able to understand German, Japanese, French, Latin, Italian and so on. I heard that Mr. Xu Guodong can speak five languages (I just heard that I can't confirm whether it is true or not). But what is certain is that one of my teachers can write papers in these five languages, which is awesome. Just three years after returning to China, the doctor became a doctoral tutor.
Therefore, if you teach yourself, recommend Japanese, which is easier to get started.
In addition, if you have passed Japanese level 1, as long as your comprehensive quality is not too bad, you can take up any job in coastal cities with a monthly salary of at least 10,000 yuan.