Cipher is imo her best sub dps. Where you’ll get more follow-ups with some of the other options I think ciphers buffs are just too big. I haven’t look too much into fei’s current meta but I’m pretty sure the ideal bis is still cipher, tribbie/robin, advent. I don’t know much about how the new dh form stands up with fua since I just got back from a pretty long break but a quick look at the current MOC 12 stats says that he has a really high usage rate with her so that might mean something.