I have cleaned up a bit and added some comments.
The System-Updater works again. Without com.google.android.gms and com.google.android.gsf it doesn’t.
Please note, that in case of an error every uninstalled package can be reinstalled by issuing the command “adb shell cmd package install-existing <package name>”
No reset necessary 
#!/bin/bash
adb devices
#adb shell pm list packages
#google
adb shell pm uninstall -k --user 0 com.google.android.onetimeinitializer
adb shell pm uninstall -k --user 0 com.google.android.apps.photos
adb shell pm uninstall -k --user 0 com.google.android.googlequicksearchbox
adb shell pm uninstall -k --user 0 com.google.android.music
adb shell pm uninstall -k --user 0 com.google.android.videos
adb shell pm uninstall -k --user 0 com.google.android.feedback
adb shell pm uninstall -k --user 0 com.google.android.backuptransport
adb shell pm uninstall -k --user 0 com.google.android.gm
#adb shell pm uninstall -k --user 0 com.google.android.gms
#com.google.android.gms seems to be crucial for the FP3 System Updater to work
adb shell pm uninstall -k --user 0 com.google.android.gmsintegration
adb shell pm uninstall -k --user 0 com.google.android.apps.restore
adb shell pm uninstall -k --user 0 com.google.android.gms.policy_sidecar_aps
adb shell pm uninstall -k --user 0 com.google.android.tag
#adb shell pm uninstall -k --user 0 com.google.android.gsf
#com.google.android.gsf seems to be crucial for the FP3 System Updater to work
adb shell pm uninstall -k --user 0 com.android.vending
adb shell pm uninstall -k --user 0 com.google.android.apps.tachyon
adb shell pm uninstall -k --user 0 com.google.android.apps.maps
adb shell pm uninstall -k --user 0 com.google.android.apps.docs
adb shell pm uninstall -k --user 0 com.google.android.syncadapters.contacts
adb shell pm uninstall -k --user 0 com.google.android.ext.services
adb shell pm uninstall -k --user 0 com.google.android.ext.shared
adb shell pm uninstall -k --user 0 com.google.android.youtube
adb shell pm uninstall -k --user 0 com.google.android.apps.messaging
adb shell pm uninstall -k --user 0 com.google.android.calendar
adb shell pm uninstall -k --user 0 com.google.android.contacts
adb shell pm uninstall -k --user 0 com.google.android.dialer
#partner
adb shell pm uninstall -k --user 0 com.google.android.partnersetup
adb shell pm uninstall -k --user 0 com.android.providers.partnerbookmarks
#To reinstall the package simply use "adb shell cmd package install-existing <package name>" in ADB.
#Example: adb shell cmd package install-existing com.google.android.gms