"saturation": { "enabled": true, "opacity": 1.0, "fadeFactor": 0.0005, "saturation": { "min": 2, "minValue": 0, "max": 8, "maxValue": 1 }, "desaturate": { "disabled": false, "opacity": 1.0 }

This snippet from the config also affects the game. In the sense that, if I lower the saturation enough, I get a gray like launcher. So it would be good if there's a comment warning about it. lest they don't know what's the culprit
(the gray do however seems to fix going into spectator when inside game though)
Fabric latest version

I highly recommend to use the gui configuration instead. You can open it by using the command /cmdclientconfig ingame. There you can change configuration on the fly and see what it does.