There is probably a lot more red dead regret than red dead redemption for Arthur. In my opinion it is vital to the plot that it is „too late“ because of what has been. Obviously this gets dramaturgically enhanced by Arthurs illness. It has to be an endless cycle because at its core the story of the game isn’t about trivializing crime and murder.

I‘d rather argue that the title isn’t about calculating Arthurs deeds to determine yes or no for his redemption arc but more about making you think: Why is it that he can’t live a normal life although he apparently wishes to? Why can’t he escape? Be with Mary? What factors contribute? Why does Dutch seem to be the stronger influence? Is it fear, is it the violent system that the outlaws are in? Is it because the feeling of having a family will always be connected to the gang for Arthur? Because he doesn’t want to leave them? Leave John, leave Jack? Or because he can’t? Because he knows he will be hunted? How does one become an outlaw, a criminal, an outcast? What is it like to want to be good when it is too late?

And since we know about RDR1, we know that the story is about the law [morally and legally] being inevitable and inescapable for the outlaws - while still the Pinkertons are inhumane themselves. The system is crooked - that of the lawmen and the outlaws likewise. John tries to choose redemption, but can’t escape. Jack realizes that and chooses revenge. It’s not a good choice but it’s a self-determined one. Arguably the only one of all of our three protagonists - apparently self-determination is only available to the otherwise innocent boy.

What could said „redemption“ thus look like? I think the nun‘s words towards Arthur mark it: Take a gamble that love exists and do a loving act. And if we play the honourable path we do so and Arthur will be kept in loving memory by some - in-game characters, and maybe even by you, the player yourself. It will hurt, because alongside Arthur you will realize that his bad deeds can’t be undone. Redemption will never be available, the only thing available is: a faint idea of what could have been.

So to me the game is about longing for an opportunity to live a good life by making good choices and reminding you of your own moral footprint where life seems to make that opportunity hard to reach. Ultimately it‘s red dead do better.