Ok.
First step is to make the ruling class deaf. Here's how:
Do you notice that your handset still picks up audio cues for ads etc?
Even though the Google assistant is "off" on your phone?
Here's how to stop allowing satan into your device.
Exit all of your apps and reboot the phone. Once the phone is to the home screen:
Go to app permissions.
Stop the google.app process.
Turn off all permissions listed in the google.app permissions section.
Disable Google.app.
Reboot the phone.
Enjoy not being monitored by Google.
<But why does this matter? I disabled it! WTF?
Research in the wild has shown that just disabling these apps is not enough; The preloaded apps cannot be uninstalled, being part of the ROM software. Being "disabled" just means that the icons have been hidden from the user in the interface; They are still useable by the system. Permissions matter; It's comparable to allowing satan into your house.
The example is for google.app specifically, but it will also work with other pre-loaded bloatware, like facebook.app and twitter.app. Apple and Microsoft are no better. Same idea applies to those: Deny permissions first, and then disable the apps and reboot.
..And, once again Q has told us the truth, proven out by research in the wild.. We are all being spied on, even without facebook or twitter loaded.