This is a "remix" of the fan shroud from Github.
The one that ships with the printer/update kits actually allows too much air to hit the hot end and can cause a thermal runaway. For a while I got by with turning the fan speed way down, but you can only go so slow.
So I found the model on Github and made a tweak to the central air flow, it doesn't stop it, just lets less through the center and more at the part.
This and a silicone sock allows me to use 60% fan without thermal runaway. So I call that a success.
Note: Please print in ABS like Prusa suggests.
Since I have the sock, I'm trying mine in PETG to see how well it lasts.
Even with the sock, PETG was getting too hot. I've printed a new one in ABS, and attached pictures. Still working well, and I've had the fan up to 80% without a thermal runaway.
This STL file has build in supports.
Loaded the STP file from Github into Fusion360 and modified as needed.
Tried my best to make the modification as seamless as possible to not restrict air flow.