Re All Is Lost: It may be semantics (BTW, that terms is not mine, it’s one that’s been around for years), but typically All Is Lost refers to the Act II end. It’s a big reversal of fate which sets the Protagonist back on their heels. To me in PYW, that’s when she discovers Ryan was involved during Nina’s assault. What does she lose? The last chance she had to live a normal life. She’s quite literally lost that option due to Ryan’s betrayal.

The battle between she and Al is what I call the Final Struggle. It’s a literal struggle. And it’s literally final in that Cassie dies.

All the rest is what I consider to be the Denouement.

Bottom line, any writer can call any plotline point anything they want. Whatever helps them write a great script.

But I certainly understand your point: When Cassie dies, the audience certainly feels like all is lost.