True color composite uses visible light bands red (B04), green (B03) and blue (B02) in the corresponding red, green and blue color channels, resulting in a natural colored result, that is a good representation of the Earth as humans would see it naturally.
Custom script: return [B08, B06, B04];
Custom script: return [B17, B06, B03];
Custom script: return [B17, B05, B02];