It's funny, sounds like you and I are on opposite journeys. For most of my life I never read non-fic unless it was for college or work. In the last five years or so I flipped and it was just a non-fic explosion; I may have gone years without reading fiction at all apart from this one book club I'm in that's half fiction.

Point is, I think I'm in a good position to answer your question.

But then you went on to give the exact answer I would have given:

Just so. Literature is life, distilled into book form. What it means to be a person, to live in the world, to struggle, to feel, to interact with others. All that blood and guts stuff. All those instruction manuals into what it's like to see the world from someone else's perspectives, all the implicit models of reality.

You can read ten books on bridges or aquaculture and what you learn there will be useful in those domain, and maybe cast a small halo onto other topics. Literature is about the universal lessons about being human, things that are hard to codify, that have been true for twenty thousand years and that will stay true.

In the years where I reduced my fiction payload by 95% I felt ... emptier, in a way. It's hard to describe. There is an "education" to being a person that you can get in ways besides reading literature, but fuck, reading literature is such a source of alpha. Even if if it brings you no joy at all, the utility of it is off the charts. But it's hard to imagine that you wouldn't get joy out of it if you followed your own heart. There's more things to your taste that are worth reading than you could read in ten lifetimes.

It's a joyous kind of training waiting for you.