[Google Home] bj00rn:
Successfully removed Google assistant!​

Prereqs​

* Rooted device with magisk installed

* De-Bloater - create magisk module to remove apks. (Not sure if this is legit or not, use at own risk)

Steps​

1. Make sure home app to something _other_ than assistant core (Im guessing device won't be happy if it's gone and device boots)

2. Install De-Bloater from fdroid or any other method

4. Open De-Bloater and grant su (i had to force close it and do this twice for removing apps to work)

5. In De-Bloater, filter on com.google.assistant and click remove for each apk

6. Click the dots i top left and click reboot

7. When device boots, assistant is now gone!

8. In magisk, check under modules and find that a module has been installed.

Result

* No more assistant! Best upside so far is that device no longer locks when network connection is lost. Settings (swipe up from bottom screen) is gone too.

* Volume control by buttons is no longer working.

Recap on investigation:​

It seems that since com.google.assistant.core is a device administrator it can't be uninstalled or disabled.

$ adb shell "su -c 'pm disable com.google.assistant.core'"
Exception occurred while executing:
java.lang.IllegalArgumentException: Unknown package: --user
at com.android.server.pm.PackageManagerService.setEnabledSetting(PackageManagerService.java:21471)
at com.android.server.pm.PackageManagerService.setApplicationEnabledSetting(PackageManagerService.java:21415)
at com.android.server.pm.PackageManagerShellCommand.runSetEnabledSetting(PackageManagerShellCommand.java:1826)
at com.android.server.pm.PackageManagerShellCommand.onCommand(PackageManagerShellCommand.java:212)
at android.os.ShellCommand.exec(ShellCommand.java:104)
at com.android.server.pm.PackageManagerService.onShellCommand(PackageManagerService.java:21998)
at android.os.Binder.shellCommand(Binder.java:881)
at android.os.Binder.onTransact(Binder.java:765)
at android.content.pm.IPackageManager$Stub.onTransact(IPackageManager.java:4860)
at com.android.server.pm.PackageManagerService.onTransact(PackageManagerService.java:4076)
at android.os.Binder.execTransactInternal(Binder.java:1021)
at android.os.Binder.execTransact(Binder.java:994)

$ adb shell "su -c 'pm uninstall -k --user 0 com.google.assistant.core'"
Failure [DELETE_FAILED_DEVICE_POLICY_MANAGER]

I tried removing the com.google.assistant.core from device administrators

$ adb shell "dumpsys package | grep -i 'com.google.assistant.core'" # Find the Receiver
5d2c3d2 com.google.assistant.core/.launcher.SystemLauncherShim
b5943e7 com.google.assistant.core/.DeviceAdminReceiver
b5943e7 com.google.assistant.core/.DeviceAdminReceiver
3883b53 com.google.assistant.core/.BootCompletedReceiver
f12f313 com.google.assistant.core/com.google.android.build.data.PropertiesServiceHolder
com.google.assistant.core/.launcher.SystemLauncherShim
com.google.assistant.core
com.google.assistant.core
com.google.assistant.core
com.google.assistant.core/.common.feedback.FeedbackFilesProvider:
Provider{ce117b9 com.google.assistant.core/.common.feedback.FeedbackFilesProvider}
com.google.assistant.core/androidx.lifecycle.ProcessLifecycleOwnerInitializer:
Provider{b421757 com.google.assistant.core/androidx.lifecycle.ProcessLifecycleOwnerInitializer}
[com.google.assistant.core.common.feedback.FeedbackFilesProvider]:
Provider{ce117b9 com.google.assistant.core/.common.feedback.FeedbackFilesProvider}
applicationInfo=ApplicationInfo{1234f41 com.google.assistant.core}
[com.google.assistant.core.lifecycle-process]:
Provider{b421757 com.google.assistant.core/androidx.lifecycle.ProcessLifecycleOwnerInitializer}
applicationInfo=ApplicationInfo{1234f41 com.google.assistant.core}
[com.google.assistant.core]
Package [com.google.assistant.core] (c01fc72):
pkg=Package{9ef68c3 com.google.assistant.core}
codePath=/product/priv-app/com.google.assistant.core
resourcePath=/product/priv-app/com.google.assistant.core
legacyNativeLibraryDir=/product/priv-app/com.google.assistant.core/lib
applicationInfo=ApplicationInfo{1234f41 com.google.assistant.core}
dataDir=/data/user/0/com.google.assistant.core
[com.google.assistant.core]
path: /product/priv-app/com.google.assistant.core/com.google.assistant.core.apk
[com.google.assistant.core]

Try to remove form device admins

$ adb shell 'su -c "dpm remove-active-admin com.google.assistant.core/.DeviceReceiver"'
java.lang.SecurityException: Attempt to remove non-test admin ComponentInfo{com.google.assistant.core/com.google.assistant.core.DeviceReceiver} 0
at android.os.Parcel.createException(Parcel.java:2071)
at android.os.Parcel.readException(Parcel.java:2039)
at android.os.Parcel.readException(Parcel.java:1987)
at android.app.admin.IDevicePolicyManager$Stub$Proxy.forceRemoveActiveAdmin(IDevicePolicyManager.java:8177)
at com.android.commands.dpm.Dpm.runRemoveActiveAdmin(Dpm.java:222)
at com.android.commands.dpm.Dpm.onRun(Dpm.java:121)
at com.android.internal.os.BaseCommand.run(BaseCommand.java:56)
at com.android.commands.dpm.Dpm.main(Dpm.java:41)
at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)
at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:338)
Caused by: android.os.RemoteException: Remote stack trace:
at com.android.server.devicepolicy.DevicePolicyManagerService.forceRemoveActiveAdmin(DevicePolicyManagerService.java:4017)
at android.app.admin.IDevicePolicyManager$Stub.onTransact(IDevicePolicyManager.java:3154)
at android.os.Binder.execTransactInternal(Binder.java:1021)
at android.os.Binder.execTransact(Binder.java:994)

I think we need a Magisk module to remove it...

Installed https://github.com/sunilpaulmathew/De-Bloater and removed all com.google.assistant.* and com.lenovo.* and apks. Reboot and Assistant is now gone!