I just used the Alfred app when I left my house and it works great even accessing from an iphone. Lots of features are pretty much free like recording and speaking/listening through the camera, there’s just a bunch of ads and you can only view it through one device simultaneously.
FireTV has a bunch of ads and it seems harder to remove on the newer models / firmwares. For Android, I would suggest something with Android TV like Chromecast with Google TV or Onn Android TV. I have no experience with apple tv so I can’t be sure.