I have not checked the edit map to see if there are any issues, but I suspect that this distance or time is just too short for Waze to bother with finding alternate routes. Unless there are significant delays on this route, then it isn't likely that an alternate route will save you much more than a few seconds.
Here is the link on the edit map so you can review connections and proper layout and allowed turns of streets you may consider as valid alternates which would save significant time:
https://world.waze.com/editor/?zoom=3&l ... =-41.28181Please ensure that you review the editing manual, link in my sig, before spending too much time making what you might believe are good and valid changes. Again, I must reiterate that I think this time/distance is too short for any alternate route to be significantly shorter or faster so Waze doesn't propose them.