Ground contact should become more meaningful under load, not disappear as soon as the weight gets heavier.
The foot, ankle, hip, trunk, and arms work as a sequence whenever you stand, step, walk, or carry. Paying attention to the ground can clarify the whole task without forcing the foot into one perfect shape.
Load is a test of the option, not a reason to abandon it. If the strategy changes completely as effort rises, adjust one variable and rebuild from a level you can understand.
Try this today
Make the idea practical.
During your strongest set, notice whether the toes grip or the heel becomes light.