I also stumbled onto Crime and Punishment at 18 and expected it to be difficult and was blown away with how Dostoyevsky wrote one of the greatest novels of all time, to be sure, but as the author here says, also how engaging he made it.

The scene where he commits the crime is an absolute stunner, edge-of-your-seat, thriller. Who does that? Who can pull that off? Dostoyevsky

Funny, I'm just reading War and Peace myself (the Anthony Briggs translation) and having the same reaction, gushing occasionally to people I know how approachable it is, and how darkly funny and modern it feels. Well, at least after passing through the first ~200 pages which are a slog. I didn't find even Tolstoy's historical musings boring, although he tends to repeat himself. And I usually suck at names, but the main characters are done so well I find them easy to remember. There aren't that many important ones despite how it seems at the start. It also serves as a fascinating peek into the daily lives of Russians of all stripes in the early 1800s.

I also had the same reaction to Crime and Punishment as the OP did.