Now about food sacrificed to idols: we know that, as you say, "We all have knowledge." Yes, that is so, but "knowledge" puffs a person up with pride; whereas love builds up.
The person who thinks he "knows" something doesn't yet know in the way he ought to know.
However, if someone loves God, God knows him.
So, as for eating food sacrificed to idols, we "know" that, as you say, "An idol has no real existence in the world, and there is only one God."
For even if there are so-called "gods," either in heaven or on earth - as in fact there are "gods" and "lords" galore -
yet for us there is one God, the Father, from whom all things come and for whom we exist; and one Lord, Yeshua the Messiah, through whom were created all things and through whom we have our being.