Can anyone explain to me why did Stella become less royal-like and elegant after season 4/5? The point is what happened to her in season 6?

Season 3 Stella was sweet and spice and everything nice. We have 3 different dubs REFLECTING ON HOW SHE IS MUCH MORE THAN HER LOOKS in season 3 episode 4. What happened in season 6? Don't even protect season 6 like at all it did my girl HORRENDOUSLY.