That makes your email box effectively a password vault. Might as well use a service designed for that such as LastPass, or 1Password.

Or better still, use a password calculator app such as https://spectre.app/

This kind of approach generates your passwords for different sites based on login information and a single password only you know. No other passwords are stored on any devices or services, not even within the app on the device you are using it on.

Which enables you to have different passwords for each service and solves the problem of "too many passwords to remember" without just having to write them all down in a dozen ways that can also be compromised.