There is nothing that you can do to the segment to improve the routing. Waze’s algorithm is just saying that the left there takes a long time to make the left and that going up and doing the u-turn is faster.
Also there is a limit/ban on Rank 1 editors for now so even unlocking from L2 won’t allow you to do anything. There is no estimated date for the ban to be lifted.
I did add a junction box to see if that will help collect the timing better. Since it requires a Rank 4 or above editor to do that unlocking the segment would not allow you to add even after the ban is lifted.
Please wait till 3 Oct to give it time to make the app and then a few days to collect data and see if that improves the algorithm’s suggested route.