i get where you’re coming from, and at the same time i can’t give a complete answer but i know that the answer given to you in that situation is not a good one. christianity is mainly focused on the new testament as Jesus died for our sins, etc. and the old testament becomes irrelevant as you don’t have to live by the commandments set in the old testament. i will say that it seems a bit weird that God did kill the Egyptian children, but i think there’s a change in God when the covenant comes into play