Attaining Corporate Privacy - current findings as of this post date - (Android 9.x; Earlier versions vary)
What we know:
The handset doesn't need a sim installed to collect data.
The handset doesn't need wifi connectivity to collect data either.
Data is collected even with airplane mode on.
All offline data collected is sent to Google once a connection is established if Google has been granted permission to do so.
Steps to deny permissions to Google's spying:
Exit all of your apps and reboot the phone. Once the phone is to the home screen:
Go to Settings → Apps & Notifications → see all apps → Google app info page.
Go to the app storage page.
Clear app cache and storage.
Stop the app process.
Go to the app permissions page.
Turn off all permissions listed on the permissions page.
Go back to the app info page.
Disable Google app.
Go to Settings → Apps & Notifications → see all apps → Google Play services info page
Go to the app storage page.
Clear app cache and storage.
(This app process can not be killed)
Go to the app permissions page.
Turn off all permissions listed on the permissions page.
Go to the app notifications page.
Disable notifications.
(This app can not be disabled)
Actions Services will display a 'Google Play services error' notification. It will try to send you to the Google Play services info page to resolve it. Do not make changes to the Google Play services page.
Go to Settings → Apps & Notifications → see all apps → Actions Services info page
Go to the Notifications page.
Turn off 'Google Play Services availability' notifications.
Call your voice mail. Phone app will also display a 'Google Play services error' notification. It will (again) try to send you to the Google Play services info page to resolve it. Do not make changes to the Google Play services page. This is how to tell if an app is attempting to make use of the Google Play API.
Go to Settings → Apps & Notifications → see all apps → Phone info page
Go to the Notifications page.
Turn off 'Google Play Services availability' notifications.
(This will need to be done for every app that shows the 'Google Play services error' message; The notification option itself does not appear in the settings until after the error is triggered for the first time, for each effected app)
Go to Settings → Security & Location → Advanced → Device admin apps
Turn off Find My Device
Select 'Deactivate this device admin app'
Go to Settings → Security & Location → Location → Advanced
Turn off Google ELS and Location Accuracy services.
Go to Settings → Security & Location → Location → Advanced → Scanning
Turn off Wi-Fi scanning and Bluetooth scanning.
Go to Settings → Connected Devices
Go to Connection preferences and turn off NFC
Go to Settings → System → Languages and input → Virtual keyboard → Gboard → Advanced
Turn off 'Share usage statistics'
Go to Settings → System → Advanced
Go to the Privacy info page (if it exists) and turn off all data sharing.
Reboot the phone. Google Assistant and Google Play Services are disabled and denied permissions to collect your data. Be advised that apps that make use of Google Play services may no longer function correctly; as always, YMMV.
<But you're not a ROM h4x0r. But it's not rooted. But they have [insert spooptool here]. Other gaslighting.
None of that matters, because this becomes a legal problem. IF it is proven that Google's ROM software (marketed as a more secure OS for Android 9.x) were to not honor user permissions settings, that could open up the parent company to millions, if not billions of dollars in damages in a class action lawsuit; Manufacturers would need to take a harder look at other, actual secure platforms, or risk losing business and money.
If you're thinking of buying a new Android phone, DO NOT SET UP THE HANDSET WITH A GOOGLE ACCOUNT ON FIRST RUN. Doing this grants Google full access to everything on the phone by default, because it brands that user ID into the phone, until it is wiped and factory reset. If you did make this mistake, fully wipe and reset the phone, and set it up without any account on first run, and set up email after. This prevents locking the phone to a user ID, and also forces the handset to ask for permission to data that would normally default to a new Google user.
https://video.foxnews.com/v/5731183327001/#sp=show-clips
https://www.naturalnews.com/2018-02-28-many-apps-can-still-track-you-even-if-you-turn-off-location-services.html