You can see it as irksome, or realize that despite the low conversion he still produces an elite total of chances, and just enjoy the way he does that, because its simply entertaining.
What I mean is you have someone like Foden or Bernie who plays a different game and takes the ball to a dangerous area three times a game and out of those three times he makes an assist or scores a goal at least once, or at least makes the right decision to create a chance. Meanwhile you have Doku who will try ten times in his way, and make a mistake eight times through the wrong decision or inaccurate pass after getting past his guy, but he will get it right twice. 2>1 in the end.
Of course its a simplification but the point is in absolute numbers he creates a lot, and people being unhappy because he doesn't both do what he does best AND make efficient decisions all the time are basically expecting him to be Messi, because thats what a hybrid of Doku and Foden/Bernie would be. Its asking too much honestly. I'd rather enjoy the eight times he creates excitement without end product, knowing that eventually he will get one right due to sheer volume.
I think Pep plays him on the left because he sees him as a project and wants to improve Doku's shooting and turn him into a scorer. But Doku is not a Mbappe/Leao type of inside forward, hes a winger who will always be better at assisting than scoring. Being on the left doesn't improve his decision making because he is doubled more easily due to the obvious choices he has, and he has too much time between receiving the ball and making that choice. He sizes up opponents for too long, overthinks and then very often he has to restart because all the options are taken away. On the right he would play more instinctive and reactive which is his game. So its basically a decision by Pep whether he wants to turn Doku into a different player (more of a forward) by developing his shooting, or to fine tune his strength which is creation, which would be better to do from the right wing because his decision making would get better there.