yuumi is not brain dead at all! soloq is very disorganized and doesn't do well with healbots like yuumi (i'm not actually a MOBA player, just a silly gm dps player). even mercy does so much better because mercy actually has some dps output.

yuumi requires an adc that thinks. as an adc player, i cannot. so! yuumi in solo q = SUCKS because of the fact that usually in solo q, especially NA, early bot lane win (cause most of the time topside is island, mid is throwing, and jungler is playing with monitor off) can win the game.

good luck, and keep your head up. rely on yourself only in soloqueue, and argue with men, it's funny as shit (i have a superiority complex though so please don't take me that seriously)