Whoever the artist is this time. If they don't swiftly improve, I suspect no one is ever gonna hire them again... if they aren't doing this deliberately.
What I suspect is that they are a hack. Someone that will show example images of the few ones they did well here as an example of "how good their previous work was" in short, a form of a con artist.
And I you don't believe me, search it up, these kind of snakes do exist in this field. They sign a contract that guarantees they get paid for the arc then they change accounts and pick the next person to cheat.
I might be wrong, but I have seen other works before (granted it was over 2 years ago atl) getting similar treatment and the authors lamenting being cheated.
I just sincerely hope it didn't happen here and that this artist will gradually improve as this arc continues.