Going by the datamined perks list, the fates of Asuna, Liz, and Kyouko was set since the beginning of Part 2. The only questions were how it will happen. Since Suguha was not part of the main story in the beginning, her fate was never revealed.
All their fate is the same aslong inoda has dirt on them that they dont want anyone to find out or Kirito himself to find out... he can make it work. Thats his plot armor.
Having just one girl that escape his grasp will make this story unrealistic now. Thats the premise of the game after all.. corruption.. why leave 1 incorruptible? Unfair... I dont know how deep is the "cousin" part generation is Kirito and Suguha are in vanilla story but aint that incest if they get together? Theres no incest tag.
Will that make sense that Kirito will just move on with her and forget everyone? Its too far gone to have good end game on this game.. like toooo far gone..
How u will even consider that good anyway.. the ending is him getting cucked or alone. Both doesn't seem a good ending... Both traumatizing.
Ok lets say he got suguha to take care of him after he learn the Truth because he probably depressed right? Is that what we aiming? A pitty end. Hes probably be in a state where non of this matter anymore.
He probably keeps remembering how inoda defile those girls he loves, knows and respect.. entering trauma again and again..
I dont think both of them will be happy.. maybe suguha is happy that this is over.. but Kirito is not..