Venus atmosphere don't have O2, N2, O3, only CO2. CO2 absorbs IR, not shortwave radiation like O2, N2, O3 do on Earth. That's why Earth is cool, Earth's moon is hot more than 100 C and Venus is hot more than 400 C. If Earth only has CO2 like Venus does than Earth surface be like 100 C like on Earth's moon. Very hot because O2, N2, O3 absorb shortwave radiation and makes Earth's air hot and Earth's surface cool.
The reason Earth's air is hot and surface is cool is because O2, N2, O3 absorb most of the powerful shortwave radiation before they hit the surface.
Venus and moon don't have O2, N2, O3, so when shortwave radiation hit their surface their surface heats to hundreds of degrees Celsius.
The smaller molecules of oxygen and nitrogen absorb very short wavelengths of solar radiation while the larger molecules of water vapor and carbon dioxide absorb primarily longer infrared radiant energy.
https://eesc.columbia.edu/courses/ees/climate/lectures/radiation_hays/