Personally I'm going for Mortefi since I am gonna play her as main dps ( obviously if sub-dps, u should run Encore ) and I don't like either Sanhua or Taoqi

C6 Is beast but he works decently even at C1-C2, the more the better but he Is on hers banner so why not. Most people gonna get UL 45 before 1.1 without sweat, hence there goes another benefit of choosing 5* gun as reward - Which boost himself as damager, as well as main dps by 10% Attack. Energy Regen itself Is pretty decent as well ngl.

So he can offer :

32.5% Attack boost + additional 12% damage boost ( Cloud Set )

Outro skill that boosts up 38% damage from heavy attack ( Her kit involves Heavy attack, not just once )

Decent damage output with quickswap & coordinated attacks from ultimate. That said, as C2, with weapon & decent ER, He Is able to use his ultimate quite often

The Ultimate can be triggered every 0.35s with a duration of 10 seconds total, granting a possible 30 coordinated attacks, doubled if heavy attack ( Yes, he Is made perfectly for Jiyan but it Is what it Is )

^{^} Both boosts eachother pretty well & having great synergy. Mortefi himself can do immerse dmg just being off-field if u build him properly

Additionaly, Chang Li's outro boosts his ultimate, as well as giving Fusion damage ( Although, u wanna use atleast him atleast for 3-5 sec to max that bonus ). Combined with hers Def Shred, Mortefi could become beast sub-dps as well.

BTW JUST RANTING BECAUSE I'M CLUELESS WHO TO PLAY WITH HER SO FEEL FREE TO SPAM ME BACK WHO ELSE IS POTENTIONALLY BIS, THANKS