If all other hints does not work, but the webcam is working in OBS, I may want to add concerning:
unfortunately the normal “Virtual Camera” from OBS as linked above is not showing as Webcam Source in vvvv (as also mentioned here: Ip cameras and gamma - #8 by andresc4) - at least it doesn’t for me on various PCs I had here at hand.
To use another OBS workaround, you might might want to consider using the OBS to Spout Plugin and receive the webcam via Spout instead.
OBS to Spout Plugin: OBS<>Spout: Bi-directional video sharing with OBS Studio from any Spout program | OBS Forums
After installation, go to “Tools → Spout Out Settings” to Start/Stop the Spout Output and set the sender name.
Then see the help patch “How to receive a spout texture” …
… or my help patch attached which gives you an an example on how to continue if you do not intend to stay in Stride, but OpenCV or Skia (converts the Spout Texture from Stride to Skia our OpenCV)
From_Spout_to_Skia_and_OpenCV.vl (27.0 KB)