Atheism

You seem to be reading between the lines at text that isn't there. The text says nothing about submission or Cain not fully submitting. Cain didn't murder his brother until after God disrespected his offering.

Genesis 4:3-5 KJV:

3 And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD.

4 And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering:

5 But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell.

It all started with God not respecting Cain's offering of the fruit of the ground.

Genesis 4:6-7 KJV:

6 And the LORD said unto Cain, Why art thou wroth? and why is thy countenance fallen?

7 If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and thou shalt rule over him.

In verse 7 god implies that Cain's offering of 'fruit of the ground' was him not doing well, and was a doorway to sin!