muu win this, i explain when muu goes invincible most assume itachi can see him with sharingan like obito did to that stone ninja but i believe that's not the case- ,muu dont have chakra sharingan can see chakra by it's color, same thing works with genjutsu it affect directly to brain chakra flow but since muu doesn't have chakra he is immune to genjutsu to eye genjutsu at least,

itachi isn't completely without chance this is just most bad opponent for him. when muu uses dust release he become viNcible yata mirror can take any release without problem so that would be good time to try amaterasu, but distance might give muu time to evade it. this is bad match up against itachi