She knows the success would die, but she didn't know the cause. The only thing people speculate in the past life was that it was due stress.
But in this life, seeing things by herself, having more information, and after finding that plant, she saw a possibility. She is not stupid, she didn't have information about this, but she is smart and get the info she had and create a diagnostic with a possibility to cure

from the beginning she knows might be happened to Ducces yet she don't know how to cure what's the purpose being advancing knowing the future. the author made the Mc stupid like being maid and has ability yet not showing it. too low progress