This is a remix

I used the original with my PI 3, but it wasn't compatible with the PI 4. I've re-drawn the lowerpart_V2 to make it compatible with the new port layout.

It easily slides into the rails on the Ender 3. The case can be assembled without any screws or you can use 4 m3 bolts to attach the two parts through the mount holes on the pi.

Putting the PI in the lowerpart is a bit of a tight fit, but putting it in at an angle with the USB and ethernet in first then pushing the pi in the rest of the way worked for me. The case will flex, but I have never had the case crack from the flexing. Just be careful some people have commented on the original that their printer was not tuned enough and they damaged their PI from forcing too much. If you are having any issues getting your PI in then scale the model up and reprint. If you do need to scale it up the recommended scaling from the original model is 101%, but others had to scale a little larger around 103%.

The presliced files are using the default ender 3 bl-touch profile in prusaslicer. (I believe the bl-touch commands will be ignored if you don't have one) You also only need to print one presliced file.