I use Iriun 4K Webcam for PC and Mac to use your Android phone's camera as a wireless or USB webcam in Windows 7 SP1 x64 Ultimate. It is supposed to support resolutions up to 4K. (Max resolution depends on the phone).
I use a Samsung Galaxy S9 with Android 10. However on Windows 7 SP1 x64 Ultimate it says that the resolution of Iriun is 640x480:
I don't see any option on the phone:
How can I change the resolution of Iriun 4K Webcam?
Skype doesn't allow me to change the webcam resolution (clicking on "webcam setting" doesn't do anything):