You can skip the Google account entirely on Android and everything still works more or less (more than a few nag screens, probably worth rooting if you go this direction).

I think that used to be the case, but I recently got an Android TV (I know it's not _exactly_ the same thing) and had no option but to log in.

Of course, creating a new account for just one device was a pain too, as Google required some verification steps which included an SMS message.

Was this the new official Google TV (which is NOT actually Android TV though likely based off of it) or a 3rd party product?

The Google TV Chromecast is an Android OS just confirm which is why Stadia doesn't work on it yet. Although you can sideload the Stadia mobile app.

You can't use the Play Store though, right? So no app installs unless you sideload from some other source?

At that point you could probably sideload one of the alternative app stores and be all set, unless FDroid like hooks into google services for things

There are alternative app stores and actually, the ones I've tried have worked pretty well. There is a way to get play store working but you'd be violating ToS technically.

This has not been my experience for either of my last two Android phones, Google would not create an account without verifying a phone number. Their support forum recommended using a land line or borrowing a friend's phone.

That's sad to hear. The situation with smartphones is magnitudes worse than VR headsets. First, VR headsets have competitive consumer-respecting alternatives (Valve Index), second, they are for now purely an entertainment device, while smartphones are semi-required to competitively function in modern society. I'm surprised no government has yet tried to address the harmful smartphone OS duopoly, the only worthwhile initiatives are from unbacked Open-Source hackers.