I think you’re quite right - that’s very close to how I saw Viv too. She’s very strong to have survived on her own in an initially hostile environment, to have built a safe and happy community and to have held those close to her together through some appalling times, but beneath her confidence she feels she has failed them, especially Sana. And in some ways, perhaps she has. So she has pinned absolutely everything on her dream of achieving peace. To her mind, that’s the only thing that will justify the suffering and loss.
For me, the saddest endings to write were the ones in which she died with no end to the war in sight, particularly if the player had betrayed her.