Well since Cain adam's first son went out from Eden also and found a wife in the land of Nod. the only way that could of happened is there were other humans on earth.
So I think there is more to the story than what is known, imo genesis 1 man are not placed into a garden.
Genesis 1
27 So God created man in His own image; in the image of God He created him; male and female He created them.
28 God blessed them and said to them, “Be fruitful and multiply, and fill the earth and subdue it; rule over the fish of the sea and the birds of the air and every creature that crawls upon the earth.”
I don't think scripture will be fully grasped anytime soon. A example is my thoughts on the day orders I totally believe day 4 is read before day 3 as such 1,2,4,3,5,6 there's no need to wonder how plants grow without sun light but I know I'm the only one who would believe in such a thing
Beauty of scripture I think is it can speak to groups of people or just one person at a time
The wife you’re talking about that Cain found is Awan. His own sister. She’s not mentioned in the Bible, but the Book of Jubilees..according to Abrahamic traditions. Now, whether you dismiss anything that’s not in the Bible is fine. This stuff can be debated to death. To me it’s not all that important…because it all goes back to the main assertion: there is a god.