Minimizing all software phoning home as much as possible, and then watching for suspicious network activity.
Also dumping the flash* contents out with JTAG. And even better than that, physically disabling the network interfaces completely and not ever connecting the device to the Internet at all.
* = also the eMMC controller internal firmware, this is where a sophisticated implant will likely reside
It's also very unlikely that the hardware would be compromised, the government doesn't want to waste a potentially high value exploit on ordinary people. If they do, they risk having their exploit captured and exposed, and thus wasting it.
but yeah, the need for privacy is oddly intertwined with AI features.