Here is a damage mod for the character Guge which multiplies his attack x600, this is a temporary solution as since this is a game file, whenever there is a game update this file goes back to normal and needs to be modified again. Place the file in Android/data/com.komoe.tgofficial/files/assets it should ask you if you want to replace, hit yes and you're good. I can do other characters but for now this should work. I have no idea if this is safe or not so
USE AT YOUR OWN RISK!