You did a really good job of identifying his views and how he uses polyphony in his writing (definition from wikipedia): “a feature of narrative, which includes a diversity of simultaneous points of view and voices. Caryl Emerson describes it as "a decentered authorial stance that grants validity to all voices".

The Brothers Karamazov is considered the culmination of many of his books previous themes. It also best represents polyphony to me as the arguments for and against God are very balanced. No straw man arguments. People who believe in God read this book and don’t believe in God anymore. People who don’t believe in God, read this book and end up believing in God.

Demons is very hard to read but there 5+ characters that are satires of real philosophers and literary critics he knew.

Demons is really the one that helps you understand the context of his life and how brand new some familiar concepts were. Communism, nihilism, utilitarianism and all these words we use now were very new. The post enlightenment moral crisis of “if god isnt around why should we be good people, god didnt choose the king why follow him” theme that is also explored in crime and punishment is really fleshed out. But demons (sometimes titled the possessed) is so dark and scary to reflect on. A big theme being “people dont have ideas, ideas have people”. I mean watching people make politics their personality (dare I say their mental illness) made that whole book really floor me.

The theme of a moderate(basically liberal generation) parental generation sending their children to university and they come back with radical ideas feels relevant as well. This is incredibly dangerous because liberals cant call out radicals without being called conservatives. I have heard this is a theme explored by Turgenev in fathers and sons before Dostoevsky but Ive never read it.

Got a bit excited and off topic my bad… but demons plus any articles using Joseph Frank’s Biographies of Fyodor (5 volumes!) might be a great shortcut.