If you live in Tokyo there's serious money to be made as a bilingual software engineer in some industries.
If you're aiming to work for a Japanese company, and you're N1 in Japanese, and native-level english, you'll probably be worth more, but I doubt it would compare to working for Google, Facebook, or Stripe in Japan.
For anyone curious this site provides some data: https://opensalary.jp/en/
I'm bilingual (brushing up on my kanji with wanikani) and considering moving to Japan, but I've always heard the comp packages aren't great.
The highest paying Japanese companies tend to pay less than 1/2 of the total comp you can expect in the bay area, but may be closer to competitive to a comp package in somewhere like Atlanta or Austin.