If you have access to AI, you could try that.
If not, either you have to ask the same actor re-do his dialog without the accent, ask him which accents he can do, or else hire someone else to re-do them.
The voice acting in general is okay to great (good overall!) but this one is bad enough that I’m here writing about it rather than playing the game.
I’m here trying to provide constructive criticism, not merely complain. Hopefully you can put this on a list somewhere; I realize it will be way down at the bottom, and that’s okay. Please, just put it on the list.