> Lighting matters much, much more than the camera setup.

That’s true if you have a decent quality camera, but the built-in camera on a laptop or the front-facing camera on a phone are generally terrible to begin with. The MacBook Pro comes with a “720p FaceTime HD” camera and I know it’s not the best on the market, but it’s more or less typical and it’s mostly garbage, except for the fact that it gets the job done and it fits where it needs to go.

Twitch is a live streaming platform primarily targeted at gamers to stream gameplay.

Twitch streamers also have very good lighting setups. A ring light at minimum, usually multiple lighting rigs.

Optimizing lighting absolutely produces bigger wins than optimizing the camera, but I've seen plenty of terrible webcams where a better camera could do wonders even with the same lighting.