How to hardwire Ring keypad without existing wiring/security system?

I'm trying to hardwire my Ring keypad and every example I've seen has been people replacing an existing keypad (i.e. ADT keypad) with the Ring keypad. I'm trying to figure out how to tie into an existing 120v line since I do not have a pre-existing wire/alarm system. Running the lines in the attic isn't an issue. The issue is finding the actual parts/equipment to do this. I must not be using the right search terms because I can't be the first person to do this. At this point I'm strongly considering piggybacking off the light switch just below where I want the keypad to go with a 120v outlet w/usb plugs and hiding it in the wall behind where the keypad with be. Feels a little jerry-rigged but I know it would work. Any suggestions would be appreciated.