It wasn't his first major work. His first major work was Notes from the Underground, which he wrote in St Petersburg in 1859.
I like Karamazov where he describes the pleasure in taking offence, you lie to yourself, make a mountain out of a molehill , then revel in your indignation. He completely dismantles that thought terminating cliche so often deployed to close down debate today .
Well, of course, my favourite is The Raw Youth. It's basically where Dostoevsky goes on to explain how science can't really find answers for the deeper human need.
Russian politics. Disagree with Putin, jail time. The end