Your fairy tale drives your "understanding". Believe the truth instead.The meaning of the Seed in Galatians is how the thing is to be viewed and resolved. That's why Paul also grappled with the huge issue of whether Judaism replaced the Promise with the Law in 3:17. They had. They stand or fall together. The Seed is Christ is what makes the mission to the nations succeed. But when you say the seed is the race/DNA/descendants, you get tangled up in them being in the land with their worship system and temple.
You are a stepchild of Judaism and need to stop talking until you have sorted out whose side you are on.