Not going into detail, but I use encrypted online backups and various offline backups, on paper and USB, including some in a safe deposit box in a former bank vault. I've learned that losing a key is a greater risk than having it stolen. Luckily, that was just a small amount of shitcoins like Peerplays, and one Steem account I never saved the password for.
And of course, keeping it on an exchange is a greater risk than keeping it on your own wallet.
I don't trust password managers, which are a single point of failure. I should mention that they're generally recommended by information security professionals.
You sound pretty sorted.
I'm not a huge fan of password managers, although you can presumably take a backup of the storage file which would likely be encrypted.