Please don't take any questions or ideas as an insult or dig. I don't know what your skill or experience level is, so I'll just ask.
Is the whole cabinet front square? To check, measure corner to corner both ways. ( left top to right bottom, right top to left bottom) be pretty precise. They should be the same if it's square.
If not, when the cabinet is standing up, you can place a shim under the front corner that measured long. Keep raising this corner until both measurements are identical. Even as robust as your cabinet is, it should flex a fair bit. I would now check the smaller divisions you first asked about. Are they close to square?
Perfectly square never happens with cabinets, but it should be close. I would now install the doors and drawers and adjust for good reveals. When I install cabinets, I sometimes have to rack the cabinet out of square to get good door and drawer spacing. Maybe more shim, maybe less. It's sometimes just trial and error.