Probably has to be when you finally get back to the "climax" as Abby and face off in a one-on-one with Ellie. Reminds me of the David fight in part 1, but with more emotional stakes

I love how being forced to play as Abby in the first Ellie vs. Abby fight puts the player into the same end result Ellie feels. Ellie is denied her revenge in this fight entirely, and the player feels the same way by having to play the fight as Abby. Had the player controlled Ellie, they would have been denied the ability to get revenge due to losing, but they would not have been denied the opportunity to try. Never controlling Ellie removes any notion the player will have before knowing the result that they will get to have a chance at revenge. For the second time, Abby controls the situation entirely just as she does in the lodge at the beginning of the game, and it eats at Ellie and is likely intended to eat at the player too. I expect the intention is to have the player be in the same shoes as Ellie when she decides to go after Abby yet again; both parties have been denied their chance at revenge and never had any control of the situation, and they feel they need that opportunity.

The risk this whole game has is the player feeling the way that Naughty Dog likely wanted them to feel. If the player ever feels different to that, it starts to fall apart. Plenty of people wanted to just kill Abby in the last fight, whereas the intention is more to make the player feel the whole fight is just pointless and wishes to just have it stop, and in the end Ellie realises this and stops the fight. It's not satisfying either way, and it isn't supposed to be. The whole point of Abby's story was to show it never satisfied her to kill Joel, and the player/Ellie are supposed to realise they will feel the same way at the end if they were to kill Abby.