v4l2-ctl --list-devices - mobile working with screen mirror but not listed as camera

[Mint-me123]

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Environment

OS: Linux Mint 21.3
Scrcpy version:3.3.4
From github for ubuntu
Device model: Samsung Galaxy A34 5G
Android version: 16

Describe the bug

I dont seem to be able to get the webcam function to work with my
samsung galaxy a34 5g using linux. The screen mirror works perfectly.

I have updated to 3.3.4
I have done the
sudo apt install v4l2loopback-dkms
and
sudo modprobe v4l2loopback

but when I test for devices
v4l2-ctl --list-devices
The samsung does not list. But the laptop webcam does as does iriun webcam (which works fine on the samsung A34 5G as well as the older Huawei P30 Pro on android 10).
I have tried 2 different USB cables, a USB hub and directly into a laptop USB. (again The screen mirror works perfectly).

So I cant call the samsung as it is not listed.
What am I missing with the scrcpy installation setup and or the calling of a v4l2 sink