It’s also worth noting that in the case of games in Japanese, it’s not so easy for developers to find alternatives. While games using English can rely on system UI fonts, cheap commercial fonts or open-source options, the sheer number of characters used in Japanese means high-quality fonts are extremely difficult and expensive to make, so few affordable alternatives are available.

There's already a decent selection of high quality, freely available Japanese fonts here: https://fonts.google.com/?lang=ja_Jpan