I'd imagine picking a highly volatile stock with a lot of wallstreetbet bros in it, like TSLA, would serve to helpfully obfuscate your trades and their relationship to the hack.
How would it be harder to launder? You bet on a Tesla stock drop. That's perfectly legal. Musk tweets some bad news, and says he was hacked, but that doesn't mean you hacked him.
Market surveillance is much better than most people realize. The accounts making money on a scam like this would be identified, filtered for anomalous activity, and the people at the other end investigated.