The most difficult part of this design are the covers, particularly the covers which need to step up and over the DIN rails. These are hinged so they can print flat, however getting the hinges right is a challenge (the first ones I printed were fused). I'm not sure if this will be the final design, but it may be close. If my prints come out OK, I will post this up to Printables.
Update 5/12/2023: The basic design for the hinged covers is working, but I now just need to tweak the fit a bit. My Ender3 also blew out it's heatbreak which set me back a bit replacing the block, heatbreak and nozzle (and having to reprint a melted air duct for it).