My family wants to build a house on the farm, but the terrain of my house and my neighbor's house to the east are the same, but the terrain of my neighbor's house to the west is 2 meters lower than my house.

Of course there is no problem in Feng Shui. The problem is your neighbor’s house to the west. Generally speaking, whose house is higher among neighbors means that whose house is higher than the others (this is why there are many fights between neighbors in our hometown). As for the terrain, I don't know much about it. I need to ask experts based on the local soil quality.