I do this routinely with an iPhone 15 Pro, although I record in ProRes LOG. I use a $20 phone holder from Amazon, a well-rated off-brand USB 3.1 hub, a Shure MV88+ mic, and an older SanDisk Extreme 1TB SSD that I was no longer using.
It works wonderfully well. The hub has two USB-C ports and a USB-C connector that I plug into the phone. The Shure mic plugs into the other USB-C port in the hub. I strap the hub and SSD to the phone frame using gaffer tape - looks downmarket but I don't care, as the results are swell.
It works without a hitch. The ProRes LOG workflow which looks so complex and scary because of the huge file sizes in 4K/60 is actually very smooth so long as you have adequate working space on your computer. I simply transfer the files from the SSD by cable to a desktop PC, open a file in Premiere Pro, apply the wonderful (free) FreeLab plugin conversion LUT, make a few simple color tweaks to taste, then export in a much, much smaller file format for YouTube.