This was actually very helpful perspective thank you

But other comments are saying the exact opposite, that Google has full and compete access to the device and its hardware at all times.

So just to confirm the answer to my question question: Its pointless to use encrypted messaging on an Android device?

Someone at Google could hear what a device’s microphone is picking up at all times?

Odd. Signal notifications absolutely include the content of the messages received.

Neither, some manufacturers modify Android considerably. By “stock” I mean essentially what is on Pixels and many other devices, but not for example, Samsung.