Using an AC1900 as an Extender or Access point or ?

My Arris Router is buried in an upstairs closet and connected to my "Open House" CAT 5 ethernet panel...so while I have wired ethernet in every room, my wifi signal is horrible downstairs. It was not a problem until I installed my wireless security cameras at the front of the house which receive a fairly poor signal. My thought is to add an AC1900 Nighthawk extender and utilize it as an access point since I have ethernet in the office at the front of the house. I already have a switch set up in that office...so I'm assuming it should be a plug and play type of install to set it up as an access point connected to the switch? My internet service is 100/100. I hope this is enough info and any suggestions would be great! While a mesh type system may be the best choice....I'm really looking for something quick and easy.