There's already commercial projects like that. Where you can have the OG voice actor to speak the other languages, thus not needing to cast more voice actors.
I suspect it will get very good and that it will be hard to tell if a real person or not. We are nearly there now with services like Eleven Labs and with the current pace of things, I suspect we are only a year or two away, maybe even there already in many ways just not consistently.
And probably not as high quality. The voice acting in thsi game is a 10/10. I doubt that, to put my own languages, it would be nearly as good in Spanish.
I've ran into some conversations were some of the characters lines noticeably sound like they're recorded from a different mic/in a different studio. Other than that it has been nice to have so much of the game voiced.