Can someone ELI5 what Agnes and Ailette talked about 😭

Cmiiw from what i understand the first part of the novel she is in created by the god with the plot Teslid regress to save the world then the god left the world without giving Teslid any definitive ending. This make the world to crumble so Teslid gonna keep regressing because whatever he do can't save the world (this what make part 2 of the novel)

To simplify it
Tesslid save the world - god left - (world facing destruction again - Teslid regress again to asave the world) repeat

Oh wow thank you so much