Hercules after killing Megara and kids does twelve grueling labors as atonement on Apollo's order.
Ajax ibn Telamon after ravaging Greek tents kills himself to preserve honor and gives his weapons to his son.
Even the virtually satanic Achilles, after losing Patroclus, polluting Xanthus and dishonoring Hector, eventually listens to Priam.
Agamemnon after killing Iphigenia nearly destroys the Greek army twice over Chryseis and over Briseis. To tell you how serious that is, know that even Diomedes, famous for hurting Ares and Aphrodite without hesitation, didn't dare to double cross Apollo.
As if crossing Apollo wasn't bad enough, Ajax ibn Oleus after raping Cassandra and dooming the Greek army with Athena's wrath boasts he's immune to even Poseidon's storms.
Whatever grief Agamemnon may have felt over Iphigenia still didn't make him anywhere near the self-aware man Greater Ajax was, let alone Hercules. Agamemnon is fundamentally a man closer to Achilles and Lesser Ajax than to Diomedes, Odysseus or Greater Ajax.