"I get hating the past him but to hate the reborn him that hasn't done anything he did in his past life and is instead actively trying to change everything for the better, just doesn't make sense."
Your entire argument hinges on separating "past" and "current" him when the are the same person. He still had all his memories, he still did all that, it's WHY he feels bad and is acting differently... what's more, SHE still has all her memories, which means there's not even really an argument for saying that "because he rewound time he didn't do it" because it's all still affecting her even now...
Enough with the excuses for him. Yes, he does better in this timeline BECAUSE HE FEELS BAD, but that doesn't give him forgiveness. If i cut off your leg and then pay all your expenses for the rest of your life, you still have the right to suffer due to missing a fucking leg and hate me for it.
IMO, it is because BOTH of them are reborn.
I'm reading "You Own My All" (The Wife First) which has a similar concept, but the MC is reborn while his husband isn't. I've forgiven MC because his husband never had to suffer bc of him.
But I hate this ML b/c BOTH of them are reborn. So, it's impossible for me to ignore the actions of their past lives. My hate for current ML is like hate for someone who has seriously wronged MC in the past and is trying to make up for it now.
If MC finds out ML is reborn, should she just forgive him bc she hasn't died this time? No, she remembers all the pain and it influences all her actions. He needs to EARN her forgiveness.
But, I'm satisfied with the actions of the reborn ML so far. Elle tortured him a bit which helps. Would be great if he went beyond just doing the basics and actually made her happy.
"If i cut off your leg and then pay all your expenses for the rest of your life, you still have the right to suffer due to missing a fucking leg and hate me for it." You've given me this same argument on another comment I made and i will say the same thing. I DID NOT SAY THE FL SHOULD NOT SUFFER OR HAVE NEGATIVE FEELINGS TOWARDS HIM. I said i didn't "get why PEOPLE (the readers) are hating on the ML". You paying my expense would mean shit all to me, I agree. My leg is gone, and it can't come back. BUT, if you could go back in time and fix things so that I never lost my leg in the first place and i found out about this, I would appreciate it a hell of alot me. The FL has every right to feel how she feels, but us the readers know something she doesn't. We have ALL had moments where we wish we could go back in time to change what we did, either small or big, because we feel bad about the decisions we made. If you could change the past for the better, you would. And he did. What he did, in my opinion i can't relate to. But what he is trying to do, righting his several wrongdoings, I can relate to. That's all I am saying. If you can't see it from my point of view, fine. I respect your opinion but just don't agree with hating the current him(the him from THIS timeline) while he is trying to save the FL and his son.
"You paying my expense would mean shit all to me, I agree. My leg is gone, and it can't come back. BUT, if you could go back in time and fix things so that I never lost my leg in the first place and i found out about this, I would appreciate it a hell of alot me."
A leg is a physical thing that could be undone even if you retained your memories, so i can see your argument there, but i feel like you're arguing the analogy instead of the point. What happened to her was traumatic, that's why time reversing does fuck all if she retains her memories.
There's also tge nuance of his intentions to discuss as well, because be went to just... erase his deeds without taking responsibility. He wasn't going to tell her, luckily she remembers so he doesn't get the freebie.

What we see in chapter 21 is his past life and what happened as a result of him following what her dumbfuck of a father said. The ML has also been reborn and he is trying to right the wrong's of his past life, to save both the FL and Elle. And let's been fair, compared to other ML's in reincarnation stories or even Remarried empress, who have actively set out to abuse and plot the death of their wives, the ML isn't that bad. I get hating the past him but to hate the reborn him that hasn't done anything he did in his past life and is instead actively trying to change everything for the better, just doesn't make sense.