I remixed the model due to the fact that the bottom keeps opening up. I added another screw at the bottom near the opening where the cable goes. Just make sure that the screw doesn't hit the thermistor cables when inserting the screw.
In PrusaSlicer, make sure that you split the part first, I provided a picture for those people who's unaware of that feature.
I use an m3x16mm screw and an m3 nut to screw the bottom part. but maybe an m3x12mm should work as well.
Thanks for Sad Money for creating and leaving a step file for this model.
The author remixed this model.