You should have anticipated this and directed airflow to the windshield before you start driving.

I have also never experienced spontaneous fogging of the windshield while I’m driving, and I live in Scandinavian weather which is both humid and cold. It’s always there when I enter the car. The AC dehumidifies the cabin air while driving so it really shouldn’t be fogging the windshield out of the blue while you’re driving.

But besides that, steering wheel control or voice control cab enable/disable this in many cars these days.