No, by all means keep experimenting, if you're so inclined. I was only expressing my surprise that it was recognized in the Windows version of iTunes at all, since I didn't think it was supported.
It turns out I was wrong though, I'm sorry about that. Apparently, it should work fine with the latest version from the Microsoft Store, see this link.
Streaming from your devices is more of a secondary function in the HomePod in the first place though. Even the Mac version of iTunes is finicky with streaming over Wi-Fi (though if you have newer iOS devices those should work fine, IME). It's best suited to stream directly from the internet connection it has, from the Apple servers using your Apple Music subscription of iCloud music library.
(This is what it tries to do even when you stream "from your device." It gets the item you want to play, position, etc., and streams it directly from the cloud if possible. Obviously if it is not iTunes content, it will stream from the device which is the only available source.)
You should definitely contact Apple support if you have made sure you have iTunes 12.9 or later and you cannot get this to work. Again, I apologize for the misinformation, I assumed it wasn't compatible because the material for HomePod doesn't mention PC support, but the PC iTunes troubleshooting manual had a section on HomePod on it.