^ ^ This.
Many, many questions would present in looking at WiFi range, especially indoors.
2-3 walls? Stone, brick, drywall, insulation? What rooms are inbetween? A kitchen, maybe? What other equipment is in between? A TV, perhaps?
Other WiFi close by (neighbors)?
I'm not looking for actual answers to those questions, but just listing a very few of the variables that can come into play with WiFi.
Buy a name brand one and see what happens.