Book where the protagonist struggles deeply with regret over something terrible they’ve done?

Can anyone recommend a book where the protagonist struggles deeply with regret over something terrible they've done? I'm looking for a story that really dives into guilt, remorse, and how they grapple with their past actions. Bonus if it's introspective and emotionally complex.

My favorite authors are Dostoyevsky (Brothers Karamazov, C&P, etc), Camus (The Fall being my favorite book of all-time), Salinger, and Raymond Carver.

Looking to find a new author that I'll love and I tend to gravitate towards books that are highly realistic and introspective.

Authors I've tried and can't get into (that are frequently recommended): Tolstoy, Murakami, Kafka.

Would love some suggestions.

Thanks!!