What do the early chapters tell you about the social, political, and religious environment of eighteenth-century Europe?

Even in Candide's early chapters, Voltaire presents Europe as a continent rife with injustice and cruelty. One might well treat it in language of the absurd (even though the modern concept of the absurd didn't really come into being until the twentieth century, I would suggest it applies here all the same). Fortune is arbitrary, and Europe itself is defined in terms of cruelty, hypocrisy, and superstition.
In the book's first chapter, Candide is driven from Thunder-ten-tronckh because he and the Baron's daughter, Cunegonde, have fallen in love with one another. Cast out, Candide finds himself (in the next chapter) tricked into conscripting into the Bulgar army, with Candide being beaten and brutalized during the military drills. In chapter 3, we see Voltaire tackle the subject of war and its pointless brutality. We are given a detailed account of the self-destructive slaughter and cruelty of war. First, we witness the Bulgars pillaging and slaughtering an Abar village, and then later Candide will find the same process being carried out against a Bulgar village by the Abars. The experience of war entails misery on both sides—from the perspective of the people caught in the middle, there is only suffering of the most brutal kind.
Religion is another key theme that arises within Candide, and it arises early on. In chapter 3, after he flees the Bulgar army, Candide arrives, impoverished, in Holland, expecting to be treated well, in accordance with Christian teachings. There is very little empathy for him, even among these supposedly good Christians. Later, he'll end up in Iberia, just in time for the Lisbon earthquake, where he'll experience the full cruelty and superstitious zealotry that can be found in religion. As we find out in chapter 6, in the wake of the earthquake, the Church determines to hold an auto-de-fé as a means of preventing another earthquake. Soon afterward, Candide will be reunited with Cunegonde, who will tell him her own story of what misfortunes have befallen her since the fall of her castle. From her, we learn how the Grand Inquisitor had been lusting after her and of his perverse arrangement with Don Issachar to divide ownership over her. His character is abominable and illustrates the depths of corruption which can be found in the Church.
This is a world where abuse, hypocrisy, and misery abound. That being said, we should be aware that this is a work of satire, so we should expect this absurdity to be a magnified and warped reflection of the reality of eighteenth-century Europe. However, Voltaire is clear in his conviction that there are very real problems that ought to be addressed, that there was something deeply dysfunctional within the world as eighteenth-century Europeans understood it. Candide represents an attempt at bringing that dysfunction to the surface and forcing these kinds of questions to be addressed and grappled with.