White March Ending, lol? [Spoilers]

[Sephyrias]

Managed to fight all the way through both the base game and now also White March 2 (with only a handful of optional bosses remaining).
Got to the point where you have to strike the Ionni meteor crystal to sink the structure together with the Eyeless.
Picked myself, thinking: "the game will surely pull a Divinity Original Sin 2 opening on me and I get saved by Ondra or whatever and washed ashore."
Lol nope, my Watcher just fuken died, credits roll included.

Now I don't know what to do. I've already beaten Thaos once before starting White March, but I want to avoid spoilers for the White March endings and PoE2 as much as I can, so I'm hesitant to look it up.
I spotted the Constitution 19 check during that ending. Didn't meet it I guess, but nobody in my party has Con 19. Highest is Durance with Con 14. Am I stuck having to sacrifice one of the npcs here?

Also, I read that you can have your PoE1 ending carry over to PoE2. Which endings are considered for that? Is there one where PoE2 starts with "the old watcher died fighting the Eyeless"?

[psychotron666]

Any of the endings where the watcher dies can't be carried over to the second one.

[Farsha]

Use items, food, potions to hit the con 19 with one character, shouldn't be that hard.
Eder can do it with no problem.

[dcain3456]

didn't you get the diving helmet?

[kaiyl_kariashi]

there's actually several ways to do that one.

One of your potential companions is just straight up immune to dying from it.

Finding a certain item can allow anyone to complete it safely.

19+ Con by some means allow that character to do it.

and a few quest choices will open up additional options that either allow anyone to complete it or give you an alternative to sacrificing a companion.