....how? There are literally hundreds of devices that will offer YouTube playback and music for as little as £30-40.

Whether it's a good idea or not is a different matter entirely, but the notion that you "have no choice" is just silly. Is someone forcing you to watch YouTube through your TV?

Is there a difference in your tv spying on you and those devices spying on you? I don’t mean this to sound confrontational or rhetorical, I really don’t know.

You can install a good OS which doesn't spy on you on external devices.

You can sometimes build your own Linux with Kodi with those devices. On the plus side, you're then not limited to use streaming services Netflix and can grab media from any place.

I do too. I bought a used Mac Mini online (any computer with a HDMI port will suffice). You get your browser on Tv. Hook up a wireless keyboard and mouse to your computer, and you can have your privacy friendly Internet TV experience.

Your TV doesn’t have an HDMI port?

I had to update my TV to get the 4k resolution correct. Otherwise the screen was green-ified.