Could you explain your reasoning a little bit more? I seriously interested. I have a couple of homepods and have had echos and very rarely use them for smart aspects. Certain automations for me have been much easier to setup via homekit vs alexa. And I find having multiple brands makes things more difficult. I don't understand your comment of universal connectivity.
Sure. By the way I do not recommend Echos, they are very intrusive, I cannot hold a conversation with anyone without that thing annoying me. I do recommend the Google speakers, specially the ones with screens as I find the audio to be very good and the screens very useful and of good quality.
Both Alexa and Google speakers do more because they are smarter, they understand what you ask them, which is something Siri struggles even with simple requests. If you are not interested on those features you still get a good device that sounds amazing (in my opinion) and costs a lot less. The universal connectivity comment relates to how I am able to connect any service I want to my device without restriction, you choose: Spotify, Pandora, YouTube, Netflix, anything really.
If you are concerned about privacy there are a couple of things you can do, one of them is proceed to setup with all permissions and then disable them all, it works, that is how I did. Google is also able to recognize you by your voice, it can detect if it is my mother or me or whoever talking to it and produce results accordingly, I find that to be creepy so I set the option to NOT recognize anyone, so there you go...