Some food for thought:
Gen 4.7- “If you do well, will you not be accepted? And if you do not do well, sin is crouching at the door. Its desire is for you, but you must master it.”
Cain did not do well to begin with. Sin is crouching at the door after you sin! And clearly, Cain and Lamech were men mastered by their sin.
Gen 4.26b- “At that time people began to call upon the name of the LORD.”
All kinds of interpretations about this verse. But I think it means that after the birth of Seth, and then Seth had his own son, people realized that God was going to keep his promise about a certain seed who would crush the head of the serpent (Gen 3.15). People realized that Yahweh, the covenant God, would keep his Word no matter what the evil one tried to do. People realized that they needed to worship this God, so at that time they began to call upon the name of Yahweh.