Indeed, the radiation coming from the sun in the visible spectrum is much larger than the microwave radiation coming off it [1]. Note: the microwave spectrum ends at ~300 GHz or 1 mm wavelength, that is 1 million nanometers, so the scale on the x-axis is wayyy too short in the image. The actual value is very, very low.

[1] https://upload.wikimedia.org/wikipedia/commons/0/0d/Effectiv...