The game engine is the same as MSGV/P.T (Fox Engine) but I know those games .gani/.mtar cannot work with PES but kinda similar. I've tested swapping animations files between PES19 and 21. Both are compatible with each other.
There's a "sort of" working tool for exporting mtar (they're kinda like a zip file for gani) to FBX for PES2017 here: https://gist.github.com/Hazuki-san/50e5ad0860d3b5e276eddf41bc2e570f
Partially documented file format here: https://github.com/kapuragu/FoxEngineTemplates/blob/main/gani.bt
The attached file is an animation where player stand still.
Example .gani and .mtar (from PES2019) files can be found below, I've also included necessary files for bones generation in the zip:
gani files.zip
body_anime_file0.zip