Read John Gardner’s assessment of it in one of his two books on writing fiction. He demolishes it, its two dimensional characters (the capitalists bad, the peasants all good,) if you ever read socrealist fiction, Steinbeck’s novel fits the template, and was widely translated in Communist countries as one of the few American novels. He visited there in the late 40s or early 50s, there are factual and fictionalized reports by Czech writers, of a useful idiot American writer extolling the virtues of socialism.
I’ve read my share of socailist realist fiction and TGOW is a whole lot better than that. That’s why it’s still read for pleasure whereas Sholokov’s ‘Quiet Flows the Don’ and Gorky’s meat and potatoes are not. There are formal elements to it that transcend its Depression Era context. And the final episode is still jaw dropping after all these decades.