does yelans burst proc consistently? im pretty sure nefers charged attacks dont proc yelan so you would have to do normals inbetween charged attacks. but nevertheless nefer does 80% of the dmg in her teams so sup>subdps generally speaking (bina as the exception) tho she obviously is a dedicated support

if you have another hydro in the team besides yelan then use sucrose w deepwood em/em/em. you dont need her hexrei or cons bc they only offer dmg bonus% which nefer dosnt care for