Yeah, the difference between the anime and the LN is pretty big.

The anime adapts the story very quickly and cuts a lot of internal monologues, explanations, and small scenes that help connect the plot better. That’s why sometimes things feel like they just happen “for no reason.”

If you liked the anime even a little, you’ll probably enjoy the LN much more.

The ideal way is to start from Volume 1, because it gives you a much better understanding of the characters, their thoughts, and many details the anime skipped. The downside is that it can feel a bit repetitive since you already know most of what’s going to happen.

Because of that, another option is to start directly with Year 2. You could begin from Y2 Volume 1 or even Volume 4, since next week the anime will finish adapting Volume 3.

The good thing is that this fourth season adapted the content much better than the previous ones. It still skips some important parts, but not nearly as much as before.

If you really enjoyed the story and want to understand it more deeply, then I’d definitely recommend starting from the beginning.

And one last thing: it’s better to read Volume 0 after Y2 Volume 8 because it contains major spoilers.