There are some private schools in Japan that don't require a high level of Japanese, and they can enroll as long as they are junior.

But I suggest that on the premise of learning the language well, you can consider going abroad for further study.

Linguistics is not good, and classes, after-school communication, and part-time jobs everywhere are restricted.

When you get used to this language, two years of postgraduate study will soon be over, and you will learn nothing.