Could someone help me find in which files are the combat / gameplay audios of the Ultimate Ninja Storm games (Storm 4 pls) ...
I want those audios of reactions, punches, characters taking damage, screams ... etc ...
In Storm 4, these combat sounds for characters should be found in XFBIN files. Long story short, these are versatile archives containing a variety of files. I wrote a guide on how to extract audio files from another CyberConnect2 game with the same (if not a very similar) format, so hopefully it should help you to extract the files you're looking for from Storm 4.
Here is my guide: https://zenhax.com/viewtopic.php?f=6&t=14704
When it comes to Storm 3, however, if you're interested in that one as well, that appears to use an older XFBIN format which is a bit more complicated. There exist tools for it, but I haven't found much success with them myself. If I happen to get help finding a way to convert from the earlier format, it will be added onto my guide in the thread linked above.
Hope this helps!