It wouldn’t make sense to baptise in the name of the son (which represents His sacrifice on the cross) if He weren’t God..would it?
His sacrifice would be meaningless unless he were God, since no none is perfect (has a perfect nature) except God, only God could live a perfect life (as Christ Jesus did), and be the perfect sacrifice for your and mine and everyone’s sins.
Only God could fulfill the Law pefectly (as Jesus did) since all human beings have broken the law, and deserve God’s wrath for them. Jesus was the perfect sacrifice, and He was fully God!!!
Speaking speculatively. Presumably Adam was perfect prior to the Fall, otherwise what would the term mean? Had he not chosen to sin, he would have lived a perfect life. Any human who did not inherit sin from Adam would presumably have the same free choice to sin or not, and therefore the same opportunity to live a perfect live.