Tested on Ender 3 Pro power supply. The section of hex wall I printed is a bit warped so the clips do not sit flush. It works though!
Possible improvements:
Use smaller section of hex wall: https://www.printables.com/model/277017-honeycomb-wall-half-tile
along with a 90 degree segment to wrap around back of power supply:
https://www.printables.com/model/173276-openscad-parameterized-honeycomb-storage-wall-90-d
v3 - Increased the thickness of the holder.
The author remixed this model.