In fact if you want to annoy people with unnecessary information 99% of people will never fucking care about:
WebP can use both the 32-bit BGRA (supports transparency) RGB color model, the yuva420p (also supports transparency) YUV color model, and also the yuv420p (does not support transparency) YUV color model.
So if you are unsure whether the best color model is RGB or YUV, you can stick with WebP since it supports both.
Proof:
ffmpeg -hide_banner -h encoder=libwebp
Encoder libwebp [libwebp WebP image]:
General capabilities: dr1 reorderedopaque
Threading capabilities: none
Supported pixel formats: bgra yuv420p yuva420p