I am looking some like the popup camera of the Oppo F11 Pro that can be connected via USB-C. Here is an example:
I think something exactly this small would be impossible as most of its connections, board and circuits are inside the smartphone. So, maybe even a little bigger would be fine as long it would not be just impossibly massive like normal webcams are for my use case.
All I need it for is to scan Pokemon TCG Live codes from booster packs I open while not at home. So for video quality as long as a QR Code is readable its fine.
I don’t know if it works on SteamOS, but I use my deck in Windows very, very frequently due to using it as a main computer and I had a giant stack of years worth of code cards from the SUMO/XY era I never touched. I just used something called Camo to used my phone as a webcam and got through the stack pretty quickly.
I imagine there might be something similar for SteamOS, especially since you can use a phone as a mouse and keyboard with KDE Connection.
Droidcam is a pretty decent option too for using Android phones as a webcam, that’s what I’ve used on Linux to accomplish similar things. Just run the droidcam server on the Steam Deck and either connect to it from the phone via local IP address or over USB.
Literally only found this out the other day, great comment. I needed head tracking for beamng to complete my setup and found my phone’s camera obviously outperformed my webcam. No latency over usb! Anyone wanting to know an easy way to head track with a webcam or phone should try to use droidcam with Open track. :)