I found a workaround for this issue.
I have an AMD Ryzen 7 7700 system with a Gigabyte B650M motherboard and Windows 11. My iPhone 14 would connect for a few seconds and then disappear. Apple Devices would not detect it, and Windows sometimes showed “Unknown USB Device (Device Descriptor Request Failed)”.
The same iPhone worked perfectly on an Intel/Dell laptop, and another iPhone (11 Pro Max) worked directly on the AMD PC.
The solution: I connected the iPhone through a USB 2.0 hub instead of directly to the motherboard USB port:
iPhone → USB cable → USB 2.0 hub → PC
After doing this, the iPhone stayed connected, appeared in Apple Devices, internal storage became accessible in File Explorer, and it also worked directly in OBS.
This appears to be a USB compatibility/negotiation issue that can be bypassed by putting a USB hub between the iPhone and the AMD desktop.