yep, can second the needing to fiddle a bit-- i've had some pretty annoying color issues as well, where i fix white balance, etc. in OBS, but the output in Hangouts/etc. looks terrible, like it's ignoring the filtering i'm doing, or there's a pixel format issue or something
It's built into 26.1 rather than requiring the plugin (which I could never get to work for me under linux), although if installed via snap you have to enable v4l2loopback manually