realistically i'm of the mind the way to "fix" the game would just be to reorder the gameplay timeline a bit and add some more early gameplay and cut some later.

JOEL NEEDS TO DIE. he is a monster. this is unchanged.

you start as young Abby. Expanded gameplay. then you play some older Abby. make her faction more interesting, make the conflict she's in more complex and nuanced <- majority of gameplay

then switch to Ellie for a short run. Abby encounter happens. Flashback to what happened to Abby's dad.

Now play Ellie revenge arc. leave all the nasty stuff, her killing Abby's friends, which now you have spent more time with than Ellie in this game

Cut the brawl between them in the last act! because fuck the Zionist who created it and his "this is actually the ancient and inscrutable conflict between "Israelis" and Palestinians" but in microcosm.

Instead Ellie walks away, realizing Abby and lev have been through so much pain that there is no need for "revenge". she breaks the cycle, has a meltdown about it, tells Abby to go and if she ever sees her again she will kill her. Abby maybe thanks her, or says nothing, i dunno somebody could better then me could write a good, moving scene

Ellie goes home, is still alone but there is hope she will rectify and settle to be a cottagecore lesbian, reflecting on her ability to give up on violence. Abby's story is only beginning, she will be the main character in the next one, possibly a bit of gameplay here and hint she has found the last of the Fireflies (...or has she??)