The biggest effect of sunspots is not from any difference in heat hitting the planet, but from the “umbrella effect”. High sunspot activity extends from the sun in all directions and deflects cosmic rays from reaching Earth and the other planets. Cosmic rays create clouds when they hit the atmosphere, and that causes cooling. So more sunspots means fewer clouds and warming. Fewer sunspots will mean cooling disproportionate to the difference in actual output from the sun.
Thanks for that explanation....