These days, paint on all cars is thermoset, which means it will always remain in a permanent solid-state. So the new clear-coat can’t be melted into the old paint. All automotive & paint manufactures do not recommend that repair shops attempt to melt or burn in the clear.
Soft edge tape, reverse-masking, or hard-line masking are three short cuts insurance companies trying to force shops to use as it reduces the claims cost. When the customer is not happy with the result, they will blame it on the repair shop.
Please keep in mind insurance companies are not repairing the car, so they will never assume any liability in writing when you are not happy, or there are issues with the repair.
Extending Clear to the Natural Breaking Point