(IDEX VC4 500) Random layer shifts despite a lot of troubleshooting

Hey, after solving a lot of other issues when setting up the 500mm V Core 4 IDEX for work I now have discovered multiple occasions of layers shifting mid-print in a long print (~8h).

My prints look quite good for some layer height (maybe a little z wobble but nothing dramatic) and then at some point the print shifts. I have not yet had the chance to observe it happen since my prints usually start somewhere around the workday and finish in my absence.

In terms of troubleshooting:

- I made sure the grub screws of the gears are aligned with the flat parts of the stepper shafts and tightened to a sane but very strong amount

- I made multiple attempts in changing belt tension. Sadly in the build guide i didn't find any direction about how to properly tighten the belts and the best I could do was compare my "floppiness" to other peoples videos, then make sure all my belts are tightened evenly and "not too hard", even though that is a very subjective value

- I tried printing a cylinder in vase mode up to a comparable height, which had no layer shifts (i mean that makes sense since height shouldn't affect movement in X or Y direction)

- I have no clue whether this issue could be related to accelleration/velocity settings? I print way faster than what my old Anet A8 could handle, but slower than my Bambu A1 Mini at home, so I guess I'm not causing issues by trying to shoot the whole thing to the moon.

- I tried to compare my IS graphs to some other peoples results but couldn't make out wheter I have good or bad results, or what else to really make of my results.

- The last thing I tried was stiffening the table my VC4 is seated on which reduced overall wobble but I still had a print fail after that