My 2 cents.
On "us", some have already mentioned the trinity, but it can also include the angels. One thing God, the angels, and man have in common is that they are intellectual beings, able to abstract forms from real objects and understand the essences of things, and in men this is a faculty of the soul, which is also immortal, like God and the angels, and it is in the soul the image of God primarily rests.
In the end, there is no answer to the kind of radical skepticism behind your question about whether we have been totally deceived. The question is by its own nature unanswerable. However if you assume that the natural function of the intellect is to know things as they are and not merely as they appear, and if you assume that the natural function of the conscience is to discern good and evil, and furthermore if you assume that natural faculties automatically work correctly on their own, then it should be self-evident that God is good.
Sure, God could have repealed original sin. But sometimes the hard way is, in the bigger picture, the finest way. God had a load of agendas afoot in letting himself be tortured and executed, among which were the final validation and confirmation of the reality of suffering, the earning of merit through sinless righteousness, and the definitive answer on whether bodily death is the end. There is also the one-upmanship directed at the devil, who tricked man into forfeiting immortality.
The concept of a chosen people is no more racist than the concept of only one kind of nonbodily intellectual being (angels) or one species of rational animal (man), or one individual "chosen one" (Jesus). All told, the choice of the Jews to be the culture to be a beacon of morality and truth was tragically ironic. They couldn't stick with the plan five minutes after leaving Egypt, tolerated syncretism for centuries, and ultimately missed the boat on the Incarnation while raking in Nobel Prizes and Gentile wealth, both of which are perks of their role as chosen people. Imo, the Jewish "race", if you can call it that, is not intrinsically better than any other "race"; rather it is ennobled by what God entrusted to it, and the mission God gave it.
In the past there have been some intrinsically evil cultures (Sodom, Amalekites) that were powerful enough to destroy the Jews or all humanity by their influence and reduce the world to abject wretchedness. God destroyed some of them with natural disasters and some of them with lost wars and extermination campaigns using the Jews as a proxy. Not all lost cultures were necessarily bad, but all bad cultures collapse in some way or another.