Fire TV is Android TV so yes it will also get the update! Unfortunately Amazon rejected the update like they often do so it will take a bit longer before the update is available on the Amazon Appstore.
edit: I just checked and it’s live now!
The newer Chromecasts with “Google TV” are just Android TV with a different launcher. If you have a remote control you have Android TV.
First post on Lemmy! (Well technically second because I borked the first one haha)
F-Droid can take a while to update, that is entirely on their side. Nothing we can do about it. As an alternative you can sideload the apk file manually.