I drew inspiration from this model, but I decided to redesign it completely from the ground up as it didn't fit properly on my heatsink.

Bambu Lab P1P Fan Duct for 40x10 or 40x20 mm Fan by suit | Download free STL model | Printables.com

The model is designed for a 40x40x20 fan (40x40x10 should be fine too) and cools the drivers and capacitors. I would recommend the 3 or 4-pin 5V model from Noctua.

I think my heatsink was 38x20. It fits perfectly for me.

In my case, I used PETG and printed it with support.

Here is a good explanation of how to connect everything to the P1P motherboard.

(1) Guide for P1P & X1(C): How to replace stock fan with noctua fan : BambuLab (reddit.com)