Looking at the OP versus an other than archaic English might help.
Genesis 6:11-13 New International Version (NIV)
11 Now the earth was corrupt in God’s sight and was full of violence. 12 God saw how corrupt the earth had become, for all the people on earth had corrupted their ways. 13 So God said to Noah, “I am going to put an end to all people, for the earth is filled with violence because of them. I am surely going to destroy both them and the earth.
Earth here is the land, not the planet.
At first, I thought that your comment was a great way of understanding the Mind of God, until I checked out the Hebrew texts for the verses referenced in your post.
The Hebrew word used in Gen. 6:13 is the same Hebrew word that was used in Genesis 1:1.
So in Genesis 6:13, it is the earth that is being spoken about. God, by also killing off all the animals that walked upon the face of the land, also destroyed the earth as it was known before the flood. That was why the purpose of the Ark was to also repopulate the earth with both humans and animals after the flood. God. after the flood, set about recreating His work of the sixth day by putting the animals in the ark, that God, Himself, had chosen and brought to the ark before He had shut it up for a year, back unto the face of the earth.
Shalom