How popular is MMA in Japan?

I’m a big MMA fan, with the UFC obviously being the biggest promotion in the world, but MMA mostly got its start in Japan during the 80’s, and then popularised during the late 90’s to mid 2000’s with Pride FC. How popular is MMA in Japan nowadays? I personally love watching Japanese promotions like Pancrase, Shooto, DEEP, and the biggest RIZIN. I’ve noticed that there are Japanese superstars in the sport that get a lot more support than even some UFC champions, there are fighters with YouTube channels that have millions of subscribers and get loads of views each video.