I'm a little surprised they're not updating the Apple TV 3rd Gen, because of potential subscription revenue with Apple Music. But if it hasn't happened yet, I doubt it.
That being said, the issues are probably with your wifi. I had similar problems last year on my iPhone 6. Apple genius recommended I set up iPhone as new (and not to restore from backup). It was a pain, as all apps had to be downloaded manually and all passwords put back in, but it solved the problem.