What tool head are you using?
Noctua has a 40x40x10mm (NF-A4x10 5V) fan that has a slightly higher output than the stock fan and a 40x40x20mm fan (NF-A4x20 5V) that is definitely higher output than the stock fan (but will require 10mm longer screws).
The manufacturer of the stock fan has higher output models but a minimum order quantity of hundreds of units!
My personal solution started with a 120mm, 120v AC muffin fan I pointed in the general direction of the tool head and that worked if I remembered to turn it off for the first few layers and turn it on for the rest (and there were failures because operator wasn’t always on the ball 
).
I have since added two 80mm 12V fans mounted on the frame of my TAZ 6 controlled by a Raspberry Pi (hat) synchronized to the speed of the cooling fans set by the gcode (M106, M107). My TAZ 6 is also connected to that Raspberry Pi running OctoPi / OctoPrint. This solved the “unreliable operator” problem 
.
BTW, I’m still using the stock fan but I have the Noctua fans on the shelf if I need them.