After trying several designs, I've found Mistral-E Cooling Duct (https://www.thingiverse.com/thing:3255518) which worked perfectly on my Ender 5.

Still, it had some room for improvement, so I did it trying to keep the good performance:

• Raised the duct 1mm, to avoid collision while printing.
• Larger and reinforced tabs for the screws.
• Larger screw holes.

Tested with my Warping/Curling test, with great results (https://www.thingiverse.com/thing:3852651).