Biggest issue with iPhone for video at the moment is the rigmarole one must go through in order to record to SSD... and get any sort of sound input like from, say, a DJI Mic 2. Only one USB-C port and attempting to use any sort of port adaptor sends you to la-la land very quickly.

Sound, not image quality, is probably the Achilles Heel for "professional" iPhone video recording at the moment.