It's good to know that it's certainly possible to get this printing in this configuration given that there are larger versions out in the wild printing successfully!
I think those massive corner blocks might actually be contributing to the z possible skipping or jumping since it adds even more weight to an already heavy Z, and since they're only kitty corner from each other, it adds to instability.
Based on everyone's thoughts, this is my plan of attack:
Update printed parts with the newer mod versions that appear much stronger. Specifically the 3 wheel carriages. Thinking of printing in PETG, but open to thoughts on this as well.
For the Open builds steel gantry plates that ride on the verticals, I kind of feel like they're likely stronger than 3D printed because they're steel, but honestly, it seems like all modern D-bots and variants use the 3 wheel adjustable printed version, and I'm thinking there is a reason for that. Anyone have experience with that? Otherwise, I'm considering replacing the steel gantry plates with the 3D printed versions, or design a 3D printed plate to support the other end of the axles at least
Convert to a 3 ball screw configuration with a single z motor drive like Phaedrux shared in his build.
Rather than cut the Z down, I'm considering just moving the rails up and bracing them roughly in the middle of the legs for a shorter but hopefully more robust 400mm cube but still the same height so it can sit on the floor comfortably. Still on the fence about this, since I now think it's possible to get this printing well even at this height with the proper bracing
Add aluminum braces at key corners with all of the screws
Properly tension the belts, they are literally flapping the breeze they're so loose. This might actually be the main cause of the issues with failed prints since I'm positive I could easily jump a tooth on the current belts.