Here is a very simple solution. In the beginning God created Adam and Eve. He created them in His likeness and image. I believe He created them tall, good-looking and extremely intelligent with the capacity to live forever. The world was nutrient rich and lush (which is why we have such enormous coal beds – formed from the lush, huge plant life before the flood). It was perfect and people were perfect so to speak. After the fall of man, they began to degenerate in size, intellect and lifespan. This is why the fossil record shows giant plant and animal life before the flood and the Bible says man’s lifespan was 900+ years. If life on earth was larger (there were dragonflies with 29” wingspans) back then why could there not be giant humans? Today we live 70-80 years and the plant and animal life is smaller and we are smaller.
Therefore, I believe that there were Nephilim or giants but that they were simply the offspring of our giant parents, Adam and Eve. Do you want to explore this topic more? I recommend Jon Gray’s book on Giants located in our store.