I'm on a new Verizon note 20, and I've never seen this icon before on any of my previous Samsung phones. Its only visible when I pull down the notifications. It's not an alarm/timer as I don't have any of them set (I've already checked). It's in the upper right, next to the 4g icon. You can look at it in the screen shot here
https://imgur.com/gallery/OgYUh2h
https://imgur.com/gallery/OgYUh2h