Arteta isn't building attacking moves, the players are. The reason it is slow is because the players are slow. Partey will try to ping one in to the forwards early and it just comes back. Saka burst past Auba like 8 times and never received the right ball because Tierney was too slow to release it, looking around like a dope and playing it sideways instead. Auba and Laca can't even trap it quickly enough to play the next pass. Arteta can't run, control, and pass it for them.
Our buildup in the first phase is OK, but unless they've got 20 yards of space, Laca, Auba, Willian, and often Pepe, are entirely helpless. They can't beat a man, can't manage any combination play, don't see each other when they do make runs, and the result is we give it to Saka or Bellerin and hope we get lucky in the box. Only Pepe offers any real jeopardy besides the 19-year-old, and Bellerin is at least a constant threat.
This isn't to let Arteta off, it's to say he has been unable to get anything like a good performance out of our attacking players, and I think it's more to do with the individuals than the system. You can't solve a player problem with tactics alone.