Feeling Lost After Major Sins, My Heart Is Dead and I Fear Allah Has Left Me

Assalamu alaikum everyone. I'm writing this because I'm totally lost and at my lowest point. I've done, and still struggle with, many big sins. I've fallen into zina, lying, envy, arrogance, and other small sins. My heart feels completely dead right now. Everything feels like it's closing in on me. My biggest fear is that I think Allah has abandoned me and left me to myself. I messed up so badly. I try to read the Quran, but I can't even understand it or feel any connection. I want to change, but I'm so overwhelmed that I don't know where to begin. Please, can someone give me practical steps on how to return to Allah when you feel this far gone? How do I bring a dead heart back to life? JazakAllah khair.