I don't want to make things difficult for myself, I save my seeds in 1 flash disk and 1 special book because I'm the type of person who is forgetful so I think a flash disk in a book is the right place to store my seeds.
So, have you ever thought about your flash drive being damaged because electronic devices are very susceptible to unexpected damage, even if you preserve them very carefully? And the fact that you only have 1 copy saved in the notebook and no other backups, have you also thought about losing it or other problems?
You should have 2 or 3 backups stored in different places, that will give more assurance to your seed phrase. Furthermore, you can also share it with your closest loved ones, don't let those bitcoins disappear with you without a relative to inherit if you encounter unexpected problems.