This isn't a great idea for a few reasons, but if you're looking for something like this, its possible to do it with a few lines of bash - Shitty Password Manager (https://github.com/nindalf/shitty-password-manager)

You may also dig https://www.passwordstore.org/

You can't grep for plaintext in an encrypted file. That's kind of the point of encryption.

I won't do this daily on my Android phone.