Really opensource should be interoperable with already existing opensource software.
There are 2 great pieces of opensource wireless audio software, squeezelite which runs on esp32 like RASPIAUDIO · GitHub or GitHub - badaix/snapcast: Synchronous multiroom audio player which runs on a Pi.
Squeezelite is more limited than Snapcast as Snapcast is a full blown opensource Sonus challenger for wirelesss multichannel audio.
You place your speakers in the best place for speakers which usually is a stereo pair on a facing wall giving room coverage.
This allows your microphone to be optimal and close and away from your speakers, but not cloning always far more choice as not only are they your smart speakers they can be cast to by any device you set up with opensource casting software.
You can pick what amplifier you wish and if each speaker is active wireless or a reciever may drive several speakers.
My setup is snapcast with a Pi that needs no enclosure as its stuck on the back of a subwoofer I got from ebay for £20 and there are a whole load of very cheap but amazing quality as class D amp boards have improved so much.
If you want a liitle more quality then *December Promotion* WONDOM OFFICIAL SHOP - Amplifier Board - Sure Electronics - ADAU1701 - 18650 charger - Sigmastudio make some great audio boards.
I have 2x bookshelf speakers which again where 2nd user ebay buys as some great bargains can be made.
Not embedding a speaker creates choice and opens up to other devices that can cast to them so those speakers can be the output for all room media not just a ‘smart speaker’ …
Also makes enclosure design much easier as the engineering that goes into the Google and the rest is actually immense, you can check out a Nest audio and its ridgid cast metal body to stop resonance in its casing to help isolate speaker from microphone array. https://www.youtube.com/watch?v=4-3VodA-Nlo
Seperating microphone just makes software and engineering needs so much easier, enclosures… stick your amps to the back of your speakers on hex pillars and feed from a 24v brick PSU… 