Use the HomePod to turn on TV and Receiver
No.  This cannot be done.

The HomePod does not have an HDMI interface (HomePod Technical Specifications), so consequently, this would be physically impossible to do.

In fact, even Mac's with an HDMI interface don't support the CEC protocol.

Incidentally, if you want to connect your HomePod to your Apple TV, this is possible as a (limited) control and as an external audio device.  The latter is self explanatory, so let's look at the former use case as detailed in this article.


  When you connect your HomePod to an Apple TV, you can control it only
  minimally, such as to pause, resume, and adjust the volume. (You can’t
  even turn off your Apple TV.) For more complex voice commands, you
  must use the Siri Remote.


Emphasis Mine

If you want to send complex commands to your Apple TV, you'll need the remote (at least at this time).