Hi @taoW75
We recommend getting a Mesh network hardware to eliminate the black spot in your premises, since it is a big house as you describe.
You are looking at a great router, but we can't assure that the whole house can be accommodated by its WiFi network alone.
We've reviewed the recommended network layout from Mercusys website, and there are some access points used, just like getting a Mesh network.
It is still your decision in the end 