Removing by ADB is fine if you are able to identify which packages should be removed or if they’re already covered by Universal Debloater. You should also use Invizible Pro to control what connections are made and block trackers.
It isn’t a system app for my phone, so maybe. You could still use something like InviziblePro or RethinkDNS to disable its internet access without root though.
Remove Google apps as part of the debloat process, restrict permissions beyond what Android allows by default for all system apps, using App Ops and Shizuku. Accomplishes the same thing as GrapheneOS.
You can make stock Android much more private. Universal debloat tool + Invisible Pro - remove unnecessary apps, restrict internet access to only the apps you want to have internet access, add a tracker blocker list.
Removing by ADB is fine if you are able to identify which packages should be removed or if they’re already covered by Universal Debloater. You should also use Invizible Pro to control what connections are made and block trackers.