See
this article for a favorable probability to get that to work.
However, once you want to start embracing sources
outside the walled garden, you are likely much better served to repurpose those HomePods for their original intent- which is
not home theater- and get yourself a good Receiver and dedicated speakers. Receiver is an excellent "central A/V hub" for
everything. For example:
- AppleTV HDMI to Receiver, Receiver HDMI out to TV
- Blu Ray HDMI to Receiver, Receiver HDMI out to TV
- Anything else HDMI to Receiver, Receiver HDMI out to TV (or just to connected speakers if wanting to listen to audio only).
All that Receiver HDMI to TV is a
single cable (one output from up to many inputs).
Bonus, this can help you get true
surround sound instead of stereo only. Want deeper bass than HPs can render? Add a subwoofer. Want real ATMOS? Put some "dumb" speakers in the ceiling. Etc.
A receiver leaps over the walls in the walled garden. Enjoy ANYTHING on the best speakers in the house.
The HP "smarts" already exist in AppleTV, any iDevice or Mac. For example, I can tell Siri to play something in my home theater and it does it.
If you like using the AppleTV remote, it will turn on the receiver when it turns on the AppleTV.