Why does Iroh deserve redemption but not Ozai

Yeah, I know, y'all are probably thinking I'm crazy for asking such an obvious question, but at least hear me out first before swarming me. I like Iroh too, the purpose of this post is to simply gather different povs.

Not that many people know that Iroh, like Ozai, was also responsible for a lot of suffering, especially during the Siege of Ba Sing Se. Coupled with the fact that Iroh was renowned as a successful general, it's likely that he has a high body count. So what is it that separates him from Ozai? What is it that makes Iroh deserving of redemption but not Ozai? What line did Ozai cross that Iroh didn't?

One of the main reasons that Zuko and Azula deserve redemption is because of their relatively young ages. But both Iroh and Ozai are grown men during the series. Iroh is probably at least 10 years older than Ozai, if not more, which means Iroh, during the Siege of Ba Sing Se, was older than Ozai during the main show. So if not for age, what other reason is there for Iroh deserving redemption.

Is it because Ozai tried to commit genocide while Iroh didn't? Is genocide the final straw to determine who deserves redemption? By that logic, Azula wouldn't deserve redemption either because she also tried to aid Ozai in his genocide and was the one who suggested it in the first place.

Once again, I'm not trying to bash Iroh here. I'm genuinely trying to see what makes him deserving of redemption but not Ozai.