Can I have just 1 WiFi network with the same Password for my whole home?
Yes. This is exactly how we always setup your wi-Fi network for you. If you have to constanty select a different Wi-Fi network depending on where you are in your house, then your Wi-Fi has not been correctly setup or is an out of date system.
You must have just 1 Wi-Fi with the same Password used wherever you are in your home.