If you don't want to install anything, there's also https://3d.kalidoface.com/ for the browser. And seems they shut it down but there was a 2D version as well: https://2d.kalidoface.com/ (both open source.)

And you might want to cross-check the OBS install instructions. I'm fairly sure it does game capture out of the box these days, so not sure if there's a need to manually install plugins from source.