The Pixel 4’s default alarm clock has the ability to snooze by waving your hand above the phone thanks to Project Soli also known as Motion Sense a radar that detects movement around the phone.
As a side note it also has the ability to snooze by saying “Okay Google, snooze”
Hello Sean, I’m sorry but so far it seems Google does not want to give access to soli to 3rd parties, although we would really like to do this and more… we could do a complete and very precise sleep reacking using Soli… we have contacted Google about this, but nobody got back to as so far…