It's probably your printer isn't as precise as mine, or yours needs to be calibrated. It might be over-extruding or something. I printed on my Prusa i3 Mk3. It all printed OK, but the joints are all so loose that the head literally falls out. The hinge isn't tight enough to hold the head in, let alone in position. The rest of it is very floppy and loose as well. I guess it's possible that mine is under-extruding, which I'll look into soon, but it's been my experience that it is just much better than many printers out there, and so things like this that work on less precise printers tend to be loose. Have you printed a tolerance test? There are a few out there, but my favorite is the one that's like a fidget spinner with tighter and tighter tolerance around the perimeter. My Mk3 printed that such that only the 0.1mm part is fused. The 0.15mm tolerance rotates within it's holder as do all the others. It seems like you've used well over .5mm of tolerance for your joints.
I appreciate you sharing your work with the community. I'm only getting into modeling things, myself, so I might not be able to do much more than the part splitting I originally asked about, but if I do manage to make any other changes or improvements, I'll definitely share it as a remix.