Easy book for a picky English learner

Hey, all!

My mom enjoys practising her English by reading and translating to me, and we're switching from comic books to novels. I'm looking to pick something that won't bore either of us. I was gonna go with Murderbot, but unfortunately, it turns out that I can't stand it. The language level was spot-on, though.

Ideally, the book will have simple but not juvenile writing and won't be overloaded with terminology and confusing made-up words. Genre-wise, she prefers (in her native language, that is) literary fiction and classics, and I'm into military, sci-fi and literary.

Any recommendations?