Madara is no weaker, especially physically, with or without 1 eye. It’s just eyes are needed for that specifics jutsu
And if Guy didn’t scale to his own power, he’d be ripping apart his own limbs from one swing and utterly pasting himself from the impact of his strikes hitting
Fail to see how Luffy is stronger. Absolutely nothing he nor Kaido did even trumps early Juubi feats