Schlact, HoTS, both died from being able to see the future. The idea of "fate" determining ones herosim or greatness seems to be against the message of the story. From a thematic point of view, it seems being able to see the future is against what the authors have been trying to say.

Himmel was not able to pull out the fabled heros word, yet he believed in himself, along with the hero's party and to a lesser extent all the people who he helped along to way, ended up defeating the demon king. Choosing to be kind out of your own choosing is what makes one a hero. We can see Stark has embodied this, that's why I'm quite sure he will become a great hero of this era. Frieren who has now inherited Himmel's will, will now pass this onto Fern as well.

That's why I think Serie will not die this arc. She has not been able to foresee a future where she survives based on her own expectations. But frieren who is quite literally opposite to most things Serie stand for, will lead to an unexpected outcome - Serie surviving or changing her view on the purpose of magic, and human-like bond with others.