Which Nighthawk Router is best for me?

I currently have an N300 Wireless Router from Netgear.  Sitting about 10 feet away from my router, I get 52.27 download speed, but the speed decreases a good bit when I go into a different room.  The house I am moving into has multiple floors, so I want to be able to get the speed I'm looking for throughout the house (i.e. bedroom, finished basement, office on 2nd floor).  Would I also need to buy something like an Eero mesh system to help get the signal everywhere I need?  I'm looking into a Nighthawk as my internet provider's serviceman told me that he's serviced a much larger house before with multiple stories and he was able to pick up a very strong signal throughout the house.  Did not have a mesh system either.