I just got my pi-hole up yesterday and having a blast going through and seeing a deeper view of what my devices are querying. Think I may have already found something suspicious on my girlfriends old laptop that was sending queries for firehose.us-west-2.amazonaws.com (possibly some kind of Dell diagnostic metrics but going to quarantine that machine until I'm sure)
I ran across another interesting one from my firestick to aviary.amazon.com.
Our guest TV that firestick has been connected to has been dormant for months I assume it has something to do with firestick updates or possibly usage tracking, but when I try looking around the internet for it I get nothing but links to "aviaries" on the amazon store LOL.
I'll try blocking it at some point and see what effect it has. Thought I'd start a topic here in case anyone else has any inside knowledge about the firestick.