The literal religious "prosperity gospel", and its various secular parallels, tell rich people they strongly-deserve to be rich: God has made them so and God's judgement is impeccable

That's not how it works in Calvinism.

Essentially, Calvin believed in predestination (at birth each human is predestined to go to Heaven or Hell and he can't change that) and believed in signs of predestination -- while you can never be certain, you can make, in LW terms, high credence estimates whether a particular person is going to Hell or Heaven. These signs revolved around pious behavior and the interesting thing is that working hard was a virtue, but spending money on unnecessary consumption was a sin. Basically, being a scrooge and accumulating money was a sign of piousness -- evidence used to update the estimate of that person going to Heaven.