Well I mean that isn't always the case. If we compare like Liv and Maddie the Disney show, in real life the actress talks like Maddie but she can change her voice drastically to play other characters. Wu Jiayi may have the same voice in real life as her character but she can change it to play different characters.
I watched a bit of arsenal military and even though her voice was different, I believe it's still her voice cause like there are little parts where you can hear the similarity.