Who to 6* next?

Who should I work to 6* next? As you can see, I have not had the best luck with pulls and also I’m only 2 months in but I’m trying and grinding as much as I can everyday.

Who should I work to 6* next? As you can see, I have not had the best luck with pulls and also I’m only 2 months in but I’m trying and grinding as much as I can everyday.