I think I heard it was modded but the links broken
Most Genius Studio Japan games are now being gate locked.
If you see any of the games being version 3.1.3. Then it's honestly impossible to mod since (again) there's been installed a firewall preventing modifications and the life.
And sadly High School Fighter is a 3.1.3 version...The sites saying that have a modded version of the game is just click baiting you to download some other stupid game.
I'm sorry for only giving you sh*tty news. But I hoped I helped even a little.