The Todoroki family is really in a tough spot currently, because I don't really see an straightforward way to satisfy all the different characters' arcs. But for me, it should have the following components:

Touya lives. This is a big one. With Tomura, you could argue that he helped bring down AFO, with Toga you could say that her heart was saved, but where Touya was left off? A death would serve no narrative purpose. Even just with an open ending, there needs to be a hope that he can get better.
Enji delivers on his "I'll watch Touya" promise. He needs to make some kind of sacrifice where he puts his family first over his hero career. What form this will take? Idk.
Shouto and Touya need a moment. That moment of connection where Touya saw Shouto as a child needs to be spoken into existence somehow. I don't expect anything as sweet or idyllic as the Tgchk or Deku-Tenko moments, but I think Shouto deserves an opening from Touya even if it comes as a sarcastic comment about favourite foods. Like something fittingly low-key that gives us a glimpse of how they could eventually down the line build something.
Enji and Rei need to take Shouto off the pedestal and embrace him as a child. Shouto getting the "family hero label" and all the expectations that come with that now needs to stop. All the kids are masterpieces in their own beautiful ways and Shouto should be embraced with the unconditional love he deserves without any pressure of who he needs to be and what he needs to deliver to get it. All the other kids too.
Public fall-out addressed. This is a bit a stress-test on a society level. I think it's a given that the Todoroki family will stand by Touya (in contrast to Toga's parents who quickly disowned her). What will happen with Touya (prison, mental clinic, house arrest, some secret rehab program) is a test to see if anything changed. Also, how the public relates to Shouto who chose to save his villain brother, who is tainted by family scandals is a big question.
In the end, I'm hoping for an open, but somewhat hopeful ending. Rei, Fuyumi and Natsuo living in the new house, Touya getting the help he needs with a rehabilitation path, Enji putting him first and Shouto while obviously will keep his family close in his heart, being freed from the "hero role" and can be free to work on his own path and joining his friends.

I don't mind if he forgives Endeavor even - I feel like that's something he may decide for himself just to be rid of the anger, but it's a difficult balance because the past cannot be forgotten. So I definitely don't want the whiplash of a sudden chummy relationship with Endeavor and Shouto being handled as Endeavor's redemption trophy.

I think also a long-overdue hug from Rei and a reason to make Shouto smile genuinely are the only things I'm hoping from the epilogue.