The unit freezing only on very hot days may mean airflow is marginal or refrigerant is low

https://winterhavenhvactroubleshooting269.image-perth.org/top-reasons-for-ac-blowing-warm-air-and-how-to-fix-them

The unit freezing only on very hot days may mean airflow is marginal or refrigerant is low. Shut it off to thaw and have a technician inspect pressures and filters.