I read above, from more than one, about a distaste for "golden age classic SF." As you see, I'm a cranky septuagenarian (and only a handful of months from octogenarian crankiness). I think I might have bought my first SF paperback about 1957 (I believe it was Clarke's Sands of Mars). High school, college, and some years after I read on and on. As I said above, I've hundreds of pbs moldering in the basement, many of which I have no memory of reading, nor much desire to do so again.
But some remain green in memory and have been read again, and more than once. So, just one recommendation: Alfred Bester's The Stars My Destination (1956) considered, here and there, as one of the best SF novels. It's actually a kind of play on The Count of Monte Cristo. A story of revenge and transformation.
Stephen King must have liked it. He used a trope from the novel in one of his short stories.