The R senate vote margin in each of those states is about double the POTUS margin.
This is what I see (looking at NYT right now):
NC - 96,689 senate vs 76,737 president - 290k estimated left to count
GA - 187,861 senate vs 103,620 president - 410k estimated left to count
So that's a 25% and 80% larger senate than presidential margin. Not quite double, but I hear your point. MI showing for Biden now, so can't do the % route.
MI - 35,102 senate vs -29,525 president - 450k estimated left to count