I am certainly no expert, but my line of work has provided me with basic knowledge about personal security. Some thoughts & an invitation to others to share more in a thread below.
If this feels overwhelming, start with the big stuff (email, anything related to finances, medical) and go through and change all of those. (1)
If you must, write it down with pen and paper and store it somewhere secure. If you don't have somewhere secure, store it somewhere no one will think to look and where you won't lose it like the pages of a book. (1)
Some resources:
nytimes.com/programs/digit…
computerworld.com/article/250806…
nytimes.com/2019/03/12/tec…