Abema is a Japanese streaming app that only works in Japan. If only there was a Virtual way to Privately Network to Japan... (It's flaky, only works sometimes. No English language support for menus and stuff.)

I use this with the companion Android app on my Android TV, works great: https://streamingtvasia.com/live-streaming-japanese-tv-himawari/

It requires a yearly subscription though, it's not free.

There's this website called aqstream. It has some Japanese and Korean live tv channels for free. Not an addon or app but I suppose someone else should be interested.