yap, you need IDA Pro. its lib Modding Not Dll.
But if you know how to mod Dll. just use the Dumper and you will get the Dummy Files, You can use Dnspy to look what you are looking for if the game is libil2cpp.
you need the global-metadata and the libil2cpp, use the Il2CppDumper-v3.2.0, after...