If you cannot uninstall them from the normal Apps screen, then they are in the system partition. Google made the install-on-setup option available starting with Marshmallow, and their Nexus 5x and 6p were the first devices to support it. This way they shipped a clean phone with minimal space eaten up by the system, and carriers could still add their crap to the phone as well.
Yeah. I have never seen that happen with my Nexus 6P though but I basically have done everything on that manually since I got it. It being rooted, I may not have noticed. I'm guessing the V30 H933 probably has that same setup being a multi-carrier model.