I don't think you can just buy a real atomic clock. There are commercially available ones, but they're more of a science-grade thing that you'd need to convince the sales guy at the manufacturer to sell to you directly.
There are clocks that can synchronize to the official ones using NTP or GPS, but they just look like regular clocks.
Just be aware, the WWVB radio sync clocks don't work so well if you don't mount them ON a window. It's a pretty weak signal if you're not near Colorado, so it might not work anywhere in your house if you live on the East Coast.
I live in MD, and had to take the fancy case off the LaCross I bought and put it in a window on the west side of the house just to get it to sync...and then it never synced again.
Wifi clocks (they use NTP to sync, just like any other internet device) are the only guaranteed way to get updates, and those are much more expensive. I decided I'll just do it by-hand.
LaCrosse clocks "work," but that definition of "work" may require some serous effort on your part. You probably can't mount it in a hallway, like most normal clocks are.
Network Time Protocol, or NTP, is how internet-connected clocks get the EXACT SAME TIME. So Wifi clocks are exactly the same accuracy as "Atomic" radio clocks.
Atomic radio clocks were created in the 1980s, before the Internet became popular, which is why they are so cheap today. It will take some time before Wifi clocks are as cheap.
The success of Alexa and home automation has finally opened the door for Wifi convenience devices in the home, so this company is adding an alarm cock to the mix. Price just needs to drop by $20, and we'll have a winner!