Here's what I discovered after some research and experimenting with using the 2023 HomePods, Apple Music and Roon (all of which I own and will keep). And thoughts on using them as a soundbar.
HomePods: After owning the original HomePods and really not getting much use out of them, I decided to try a pair of the 2023 version. After messing around with using them as a stereo pair for Roon, Apple Music and for Dolby Atoms speakers for my office TV, I was quite satisfied with the purchase and versatility. However, one the software stabilized, it turns out you can use them as a stereo pair as speakers for your TV or a as an audio stereo pair, but not both. If they are being used for TV speakers you cannot send audio to them over AirPlay without getting a warning message. This is a good thing from my POV as the HomePods would not stay synchronized with each other and often one would drop out. IOS 17 changed that by locking the configuration to configured exploits and not allowing any others such as using them for TV stereo speakers and audio.
Reconfiguring them is quick and easy, so you can switch back and for relatively easy.
Apple Next Steps: Apple is extending its interoperability outside of its ecosystem to Windows by adding a Windows app for Apple Music (currently as a preview) from the Microsoft Store that is actually quite useful and does have rudimentary features that provide a 10-band Equalizer with standard presets you would find on all Apple devices, e.g., Acoustic, Bass Booster/Reducer, Classical, Rock, Jazz, Deep, Electronic, Latin, Lounge and about 15-20 others; not your typical EQ, however I use Peace and APO on Win11 for equalization, rather than the presets in the Apple Music App. Hopefully, they will add the ability to develop your own EQ for their app.
The Windows Store offers different options for improving sound quality via Dolby Atmos for Headphones, DTS Headphone:X, DTS:X Ultra, as does Apple Music with Dolby Atmos. The Windows Store Apps "Dolby Access", provides Dolby Atmos for Headphones and as a separate product, Dolby Atmos for home theater. The DTS "Sound Unbound" app offers the two DTS products.
RE Soundbars: A much better Atmos soundbar is the Sennheiser AMBEO Soundbar (they only have one), on sale now for $1700, $800 off. You need to hear it to believe it. It's quite open, you can send multichannel sound to it, e.g., I use ripped SACD Multi-channel files and Jriver to stream to it, or more simply, I use the Apple Music App on Apple TV over HDMI to stream Dolby Atmos music to it. You can use the Sennheiser App to see what codec it's using, and when Apple's Spatial Music plays it indicates Dolby Atmos True HD and indicates the number of channels. BTW: Sennheiser's support is very good, they've answered interesting questions
from me and are very helpful with detailed information about what the equipment can do. And yes, it does have its own room calibration and accepts audio in almost any format.