I stick to the old proven methods of pen and paper, along with some of my own ideas on how to protect such data even if someone were to get hold of it.
I do the same thing as you, just as i back up my seed phrases on paper, i also manage my passwords or any sensitive data on paper. However, for some reasons i know some people may not like the idea of writing their passwords on paper, so i also recommend open source password managers to them, i.e. KeePass, but for now i am yet to see a need to use them, since paper and pen works fine for me.