Camera as usb device

I have a Raspberry Pi (Debian version: 12 bookworm)with a camera module attached, and I want to use it as a webcam. I'm a beginner with this kind of setup, so I followed the instructions from here: https://www.raspberrypi.com/tutorials/plug-and-play-raspberry-pi-usb-webcam/ . It worked perfectly, but then I wanted to add a filter. So, I tried to create a virtual camera device using v4l2-ctl and intended to use that as the source for the usb-gadget script. I then wrote a Python script that takes input from the real camera, applies the filter, and sets the output as the input for the virtual camera. However, the usb-gadget script doesn't recognize the virtual camera, and now I'm stuck. How can I make this device act like a USB camera when attached to a PC if I use something other than the script from the tutorial?